D.Sc., Tohoku University, Mar. 1991

Photobioligy

Soft Crystal

Luminescence chemistry

Bioluminescence & chemiluminescence

Photochemistry

Organic chemistry

Nanotechnology/Materials, Green/sustainable/environmental chemistry

Nanotechnology/Materials, Molecular biochemistry

Nanotechnology/Materials, Biochemistry

Nanotechnology/Materials, Functional solid-state chemistry

Life sciences, Bioorganic chemistry

Nanotechnology/Materials, Structural/physical organic chemistry

Apr. 2012 - Present
The University of Electro-Communications, Graduate School of Informatics and Engineering, Professor, Japan

Apr. 2007 - Mar. 2012
The University of Electro-Communications, Graduate School of Informatics and Engineering, Associate Professor, Japan

Mar. 1998 - Mar. 2007
The University of Electro-Communications, Faculty of Electro-Communications, Associate Professor, Japan

Apr. 1996 - Feb. 1998
電気通信大学電気通信学部, Faculty of Electro-Communications, Lecturer, Japan

Apr. 1991 - Mar. 1996
The University of Electro-Communications, Faculty of Electro-Communications, Assistant Professor, Japan

Apr. 1988 - Mar. 1991
Tohoku University, Graduate School, Division of Natural Science, Department of Chemistry, 博士後期課程, Japan

Apr. 1986 - Mar. 1988
Tohoku University, Graduate School, Division of Natural Science, Department of Chemistry, 博士前期課程, Japan

Apr. 1982 - Mar. 1986
Tohoku University, Faculty of Science, Department of Chemistry, Japan

Mar. 1982
埼玉県立大宮高等学校, 普通科, Japan

Apr. 2013 - Present
世話人, 生物発光化学発光研究会, Society

Jan. 2024 - Dec. 2025
Executive Director, The Japanese Photochemistry Association, Society

May 2022 - Sep. 2023
Local Organizing Committee, 31th International Conference on Photochemistry (ICP 2023) の Local Organizing Committee, Others

01 Jan. 2018 - 31 Dec. 2021
理事, 光化学協会, Society

Synthesis and anti-tumor activities in human leukemia-derived cells of polyenylpyrroles with a methyl group at the conjugated polyene terminus
Tomoya Higashi; Chihiro Yoshida; Yoshifumi Hachiro; Chihiro Nakata; Azusa Takechi; Takuya Yagi; Kazuya Miyashita; Nobuo Kitada; Rika Obata; Takashi Hirano; Takahiko Hara; Shojiro A. Maki
Bioorganic & Medicinal Chemistry Letters, Elsevier BV, 95, 129471-129471, 15 Sep. 2023, Peer-reviwed, To develop novel drugs for treating T-cell acute lymphoblastic leukemia (T-ALL) and acute myeloid leukemia (AML) which are highly malignant hematological tumors, a series of analogs having a polyenylpyrrole structure of natural compounds (rumbrin and auxarconjugatin B) were synthesized and investigated their structure–activity relationships (SAR) of in vitro anti-T-ALL and anti-AML activities. We obtained three findings: (1) introduction of a methyl group at the conjugated polyene terminus enhanced anti-T-ALL activity, (2) analogs with a 3-chloropyrrole moiety had even higher selectivity for T-ALL cells, and (3) some analogs were effective against AML-derived cells. Among the studied compounds, 3-chloro-2-(8-ethoxycarbonylnona-1,3,5,7-tetraenyl) pyrrole 4e was the most promising candidate of T-ALL- and AML-treating drug. This study provides useful structural information for designing novel drugs treating T-ALL and AML.
Scientific journal, English

An Inhibition Effect on an Intracrystalline Reaction by a Crystal Lattice: Analyses of the Chemiluminescence Reaction of 9,10-Diphenylanthracene Endoperoxide Initiated by Heating of a Crystal Sample
Norihisa Yamasaki; Chihiro Matsuhashi; Hironaga Oyama; Hidehiro Uekusa; Junko Morikawa; Meguya Ryu; Tetsuya Tsujii; Naofumi Nakayama; Shigeaki Obata; Hitoshi Goto; Shojiro Maki; Takashi Hirano
Corresponding, Bulletin of the Chemical Society of Japan, The Chemical Society of Japan, 96, 8, 793-801, 19 Jul. 2023, Peer-reviwed, Heating crystal samples of 9,10-diphenylanthracene endoperoxide (1) and its deuterated derivative (1-d10) to 200 °C led to singlet-oxygen chemiluminescence (CL) from the mixtures of the crystalline and molten states. To understand the events in the heated samples, the reactions of 1 and 1-d10 in crystals were investigated by powder X-ray diffraction measurements and thermal analyses. The used crystals of 1 and 1-d10 obtained from a mixture of ethyl acetate (EA) and n-hexane contained EA. Other crystals of 1 obtained by slow recrystallization with the same solvents had a solvent-free structure (form II) different from the reported one (form I). The results confirmed that the EA-containing crystals of 1 and 1-d10 were transformed to form II in two steps at 40–50 and 60–75 °C under heating at elevated temperature. Thus, the crystal samples had the form-II structure soon after heating to 200 °C. The behavior of the heated samples indicates that the crystal lattice inhibits the thermal reactivity of 1. Thus, the temperature for initiating the thermolytic reaction of 1 becomes higher than the melting point. An exploration of the potential energy surface (PES) obtained by density functional theory (DFT) calculations also supports that the deoxygenation of 1 is prevented by retaining the anthracene framework in the crystalline state. This study indicates that the method to use a CL-active compound is a powerful tool to analyze the reaction behavior in the crystalline state.
Scientific journal, English

S-Series Coelenterazine-Driven Combinatorial Bioluminescence Imaging Systems for Mammalian Cells
Genta Kamiya; Nobuo Kitada; Tadaomi Furuta; Takashi Hirano; Shojiro A. Maki; Sung-Bae Kim
International Journal of Molecular Sciences, MDPI AG, 24, 2, 1420-1420, 11 Jan. 2023, Peer-reviwed, True, A unique combinatorial bioluminescence (BL) imaging system was developed for determining molecular events in mammalian cells with various colors and BL intensity patterns. This imaging system consists of one or multiple reporter luciferases and a series of novel coelenterazine (CTZ) analogues named “S-series”. For this study, ten kinds of novel S-series CTZ analogues were synthesized and characterized concerning the BL intensities, spectra, colors, and specificity of various marine luciferases. The characterization revealed that the S-series CTZ analogues luminesce with blue-to-orange-colored BL spectra with marine luciferases, where the most red-shifted BL spectrum peaked at 583 nm. The colors completed a visible light color palette with those of our precedent C-series CTZ analogues. The synthesized substrates S1, S5, S6, and S7 were found to have a unique specificity with marine luciferases, such as R86SG, NanoLuc (shortly, NLuc), and ALuc16. They collectively showed unique BL intensity patterns to identify the marine luciferases together with colors. The marine luciferases, R86SG, NLuc, and ALuc16, were multiplexed into multi-reporter systems, the signals of which were quantitatively unmixed with the specific substrates. When the utility was applied to a single-chain molecular strain probe, the imaging system simultaneously reported three different optical indexes for a ligand, i.e., unique BL intensity and color patterns for identifying the reporters, together with the ligand-specific fold intensities in mammalian cells. This study directs a new combinatorial BL imaging system to specific image molecular events in mammalian cells with multiple optical indexes.
Scientific journal, English

C-Series Coelenterazine-Driven Bioluminescence Signature Imaging
Genta Kamiya; Nobuo Kitada; Tadaomi Furuta; Takashi Hirano; Shojiro Maki; Sung Bae Kim
International Journal of Molecular Sciences, MDPI AG, 23, 21, 13047-13047, 27 Oct. 2022, Peer-reviwed, True, The present study introduces a unique BL signature imaging system with novel CTZ analogues named “C-series.” Nine kinds of C-series CTZ analogues were first synthesized, and BL intensity patterns and spectra were then examined according to the marine luciferases. The results show that the four CTZ analogues named C3, C4, C6, and C7, individually or collectively luminesce with completely distinctive BL spectral signatures and intensity patterns according to the luciferases: Renilla luciferase (RLuc), NanoLuc, and artificial luciferase (ALuc). The signatural reporters were multiplexed into a multi-reporter system comprising RLuc8.6-535SG and ALuc16. The usefulness of the signatural reporters was further determined with a multi-probe system that consists of two single-chain probes embedding RLuc8 and ALuc23. This study is a great addition to the study of conventional bioassays with a unique methodology, and for the specification of each signal in a single- or multi-reporter system using unique BL signatures and patterns of reporter luciferases.
Scientific journal, English

Quantum yield of near-infrared bioluminescence with firefly luciferin analog: AkaLumine
Ryohei Ono; Keita Osawa; Yutaka Takahashi; Yoshifumi Noguchi; Nobuo Kitada; Ryohei Saito-Moriya; Takashi Hirano; Shojiro A. Maki; Keisei Shibata; Hidefumi Akiyama; Ken-ichiro Kanno; Hideyuki Itabashi; Miyabi Hiyama
Journal of Photochemistry and Photobiology A: Chemistry, Elsevier BV, 434, 114270-114270, 22 Sep. 2022, Peer-reviwed, True, We investigated bioluminescence with d-AkaLumine, which is a firefly luciferin analog producing 675-nm light through chemical reaction with O2, ATP, and Mg2+ in native firefly luciferase, and is useful for in vivo imaging. Using a total-photon flux spectrometer system calibrated for 450–950 nm, we evaluated the bioluminescence quantum yield for d-AkaLumine, characterizing the concentration of d-AkaLumine solutions using qNMR spectroscopy and HPLC measurements. We found that the bioluminescence quantum yield for d-AkaLumine with Photinus pyralis is insensitive to pH and that its value is 4.0 ± 0.5 %. The bioluminescence spectrum for d-AkaLumine is well fit by two simple Gaussian components. The decay rate for d-AkaLumine is very sensitive to the pH value, and it increases to 7.0×10−2 sec−1 at pH 8.0. For stable absorption spectra for 4–20-μM AkaLumine aqueous solutions, we determined the molar extinction coefficient at 490 nm to be 3.33×104 L/mol cm.
Scientific journal, English

Analyses of chemiluminescence reactions of fluorophore-linked 1,2-dioxetane isomers in crystals heating at elevated temperature including a development of a simultaneous measurement method of thermal diffusivity and light emission for a single crystal
Chihiro Matsuhashi; Hiroki Fujisawa; Meguya Ryu; Tetsuya Tsujii; Shojiro Maki; Junko Morikawa; Takashi Hirano
Corresponding, Analytical Sciences, Springer Science and Business Media LLC, 38, 8, 1019-1024, 06 Jun. 2022, Peer-reviwed, True, It has been found that a fluorophore-linked adamantylideneadamantane 1,2-dioxetane derivative showed an isomeric difference in the reactivities of crystalline-state chemiluminescence (CL) under isothermal heating conditions, while there are still unsolved problems on the conditions for intracrystalline reactions. To confirm the suitable heating conditions for initiating crystalline-state CL reactions of the isomers, the CL reactions in their crystal samples heated at elevated temperature were investigated with monitoring of CL light emission and thermogravimetry-differential thermal analysis (TG-DTA) measurements together with a simultaneous measurement method of thermal diffusivity and light emission, to provide the information on suitable temperature range for the crystalline-state CL reactions and on the reactivities depending on open and closed conditions of the crystal samples. The newly developed simultaneous measurement method provides a methodology for a single crystal to analyze the relationship between a change of the thermophysical property of inside of the crystal and the progress of a crystalline-state CL reaction.
Scientific journal, English

A stable chemiluminophore, adamantylideneadamantane 1,2-dioxetane: from fundamental properties to utilities in mechanochemistry and soft crystal science
Takashi Hirano; Chihiro Matsuhashi
Lead, Journal of Photochemistry and Photobiology C: Photochemistry Reviews, Elsevier BV, 51, 100483-100483, Jun. 2022, Peer-reviwed, Invited, True, Chemiluminescence (CL) is a luminescence phenomenon originated by a “chemical reaction.” CL provides a basis for real-time imaging technology in materials science. In fact, a CL reaction is easily triggered in general and makes it possible to track its progress in a target material by highly sensitive photon detection. Recently, real-time CL imagings became breakthrough techniques for analyzing the molecular mechanisms of failures of polymeric materials and of reactions and phase transitions in soft crystals. In the CL imaging techniques, adamantylideneadamantane 1,2-dioxetane (Adox) has been adopted as a stable core structure of chemiluminophores. That is, Adox is an essential seed compound to design a chemiluminophore with a desired molecular function. To support developments of real-time CL imaging techniques, we review the chemistry of Adox as a representative stable chemiluminophore including scientific history and utilities of Adox and its derivatives.
Scientific journal

Crystalline-state chemiluminescence reactions of two-fluorophore-linked adamantylideneadamantane 1,2-dioxetane isomers accompanied by solid-to-solid phase transitions
Chihiro Matsuhashi; Hironaga Oyama; Hidehiro Uekusa; Ayana Sato-Tomita; Kouhei Ichiyanagi; Shojiro Maki; Takashi Hirano
Corresponding, CrystEngComm, Royal Society of Chemistry (RSC), 24, 18, 3332-3337, May 2022, Peer-reviwed, True, Structural isomers (cis–syn, cis–anti and trans isomers) of adamantylideneadamantane 1,2-dioxetane having two fluorophore side chains were prepared and their chemiluminescence (CL) properties in the crystalline state were investigated. The real-time monitoring of CL reactions of the isomers in the crystalline state showed contrasting isomeric differences in the reactivities and led to the finding that the crystalline-state CL reactions of cis–syn and cis–anti isomers proceeded accompanied by characteristic solid-to-solid phase transitions.
Scientific journal, English

Intracrystalline Kinetics Analyzed by Real-Time Monitoring of a 1,2-Dioxetane Chemiluminescence Reaction in a Single Crystal
Chihiro Matsuhashi; Hiroki Fujisawa; Meguya Ryu; Tetsuya Tsujii; Junko Morikawa; Hironaga Oyama; Hidehiro Uekusa; Shojiro Maki; Takashi Hirano
Corresponding, Bulletin of the Chemical Society of Japan, The Chemical Society of Japan, 95, 3, 413-420, 15 Mar. 2022, Peer-reviwed, True, Adamantylideneadamantane 1,2-dioxetane (Adox), one of the most stable 1,2-dioxetanes, was used to investigate the kinetic properties of its chemiluminescent thermolytic reaction in the crystalline state by monitoring chemiluminescence (CL) in real time. Soon after heating of single crystals at 140 °C, it was found that the thermolytic reactions of Adox in the crystals proceeded with zero-order kinetics for several minutes. During the period showing the zero-order kinetics, CL intensities were dependent on the volumes of crystals, and the inside crystals were maintained in a thermal steady state with a constant thermal diffusivity. After this period, the heated crystals of Adox started to break showing different kinetics. This study indicates that a crystalline-state CL reaction is useful to track its progress in real time for analyzing the kinetics.
Scientific journal, English

Singlet-oxygen Chemiluminescence from Heated Crystal Samples of 9,10-Diphenylanthracene Endoperoxides
Norihisa Yamasaki; Chihiro Matsuhashi; Shojiro Maki; Takashi Hirano
Corresponding, Chemistry Letters, The Chemical Society of Japan, 50, 9, 1681-1683, 26 Jun. 2021, Peer-reviwed, True, Thermolytic reactions of 9,10-diphenylanthracene endoperoxide (1) and its derivatives having deuterated phenyl groups and phenyl groups with fluorinated substituents were investigated as chemiluminescence (CL) reactions proceeding by heating crystal samples. While heated crystals of 1 showed negligible CL, CL emissions from singlet oxygen (1O2) generated by thermolyses of the derivatives were observable in the heated solid-liquid mixture states, indicating that the modifications for the derivatives were effective to suppress the 1O2 deactivation.
Scientific journal, English

Development of phenyl oligoene-type firefly luciferin analogues with extended π-electronic conjugation for near-infrared bioluminescence
Kamiya, G; Kitada, N; Saito-Moriya, R; Obata, R; Iwano, S; Miyawaki, A; Hirano, T; Maki, S
Chemistry Letters, The Chemical Society of Japan, 50, 08, 1523-1525, 20 May 2021, Peer-reviwed, True, Firefly bioluminescence, which produces high-efficiency light, is widely used in life science applications. For in vivo bioluminescence imaging, the near-infrared range (650–900 nm) is suitable because of its high permeability in deep biological tissues. In this study, we synthesized new luciferin analogues that emit light at 765 nm using Photinus pyralis luciferase.
Scientific journal, English

Synthesis of polyenylpyrrole derivatives with selective growth inhibitory activity against T-cell acute lymphoblastic leukemia cells
Chihiro Yoshida; Tomoya Higashi; Yoshifumi Hachiro; Yuki Fujita; Takuya Yagi; Azusa Takechi; Chihiro Nakata; Kazuya Miyashita; Nobuo Kitada; Ryohei Saito; Rika Obata; Takashi Hirano; Takahiko Hara; Shojiro A. Maki
Bioorganic & Medicinal Chemistry Letters, Elsevier BV, 37, 127837-127837, 22 Feb. 2021, Peer-reviwed, True, T-cell acute lymphoblastic leukemia (T-ALL) is a hardly curable disease with a high relapse rate. 20 analogs were synthesized based on the structures of two kinds of fungi-derived polyenylpyrrole products (rumbrin (1) and auxarconjugatin-B (2)) to suppress the growth of T-ALL-derived cell line CCRF-CEM and tested for growth-inhibiting activity. The octatetraenylpyrrole analog gave an IC50 of 0.27 μM in CCRF-CEM cells, while it did not affect Burkitt lymphoma-derived cell line Raji and the cervical cancer cell line HeLa, or the oral cancer cell line HSC-3 (IC50 > 10 μM). This compound will be a promising compound for developing T-ALL-specific drugs.
Scientific journal, English

Color-tunable bioluminescence imaging portfolio for cell imaging
Shota Tamaki; Nobuo Kitada; Masahiro Kiyama; Rika Fujii; Takashi Hirano; Sung Bae Kim; Shojiro Maki
Scientific Reports, Springer Science and Business Media LLC, 11, 1, 2219-10 pages, 26 Jan. 2021, Peer-reviwed, True, The present study describes a color-tunable imaging portfolio together with twelve novel coelenterazine (CTZ) analogues. The three groups of CTZ analogues create diverse hues of bioluminescence (BL) ranging from blue to far red with marine luciferases. We found that the hue completes the whole color palette in the visible region and shows red-shifted BL with a marine luciferase: for example, Renilla luciferase 8 (RLuc8) and Artificial Luciferase 16 (ALuc16) show 187 nm- and 105 nm-redshifted spectra, respectively, by simply replacing the substrate CTZ with 1d. The optical properties of the new CTZ analogues were investigated such as the kinetic parameters, dose dependency, and luciferase specificity. The 2-series CTZ analogues interestingly have specificity to ALucs and are completely dark with RLuc derivatives, and 3d is highly specific to only NanoLuc. We further determined the theoretical background of the red-shifted BL maximum wavelengths (λ_BL) values according to the extended π conjugation of the CTZ backbone using Density Functional Theory (DFT) calculations. This color-tunable BL imaging system provides a useful multicolor imaging portfolio that efficiently images molecular events in mammalian cells.
Scientific journal, English

A Very Bright Far-Red Bioluminescence Emitting Combination Based on Engineered Railroad Worm Luciferase and 6′-Amino-Analogs for Bioimaging Purposes
Vadim R. Viviani; Vanessa R. Bevilaqua; Daniel R. de Souza; Gabriel F. Pelentir; Michio Kakiuchi; Takashi Hirano
International Journal of Molecular Sciences, MDPI AG, 22, 1, 303-303, 30 Dec. 2020, Peer-reviwed, True, Beetle luciferases produce bioluminescence (BL) colors ranging from green to red, having been extensively used for many bioanalytical purposes, including bioimaging of pathogen infections and metastasis proliferation in living animal models and cell culture. For bioimaging purposes in mammalian tissues, red bioluminescence is preferred, due to the lower self-absorption of light at longer wavelengths by hemoglobin, myoglobin and melanin. Red bioluminescence is naturally produced only by Phrixothrix hirtus railroad worm luciferase (PxRE), and by some engineered beetle luciferases. However, Far-Red (FR) and Near-Infrared (NIR) bioluminescence is best suited for bioimaging in mammalian tissues due to its higher penetrability. Although some FR and NIR emitting luciferin analogs have been already developed, they usually emit much lower bioluminescence activity when compared to the original luciferin-luciferases. Using site-directed mutagenesis of PxRE luciferase in combination with 6′-modified amino-luciferin analogs, we finally selected novel FR combinations displaying BL ranging from 636–655 nm. Among them, the combination of PxRE-R215K mutant with 6′-(1-pyrrolidinyl)luciferin proved to be the best combination, displaying the highest BL activity with a catalytic efficiency ~2.5 times higher than the combination with native firefly luciferin, producing the second most FR-shifted bioluminescence (650 nm), being several orders of magnitude brighter than commercial AkaLumine with firefly luciferase. Such combination also showed higher thermostability, slower BL decay time and better penetrability across bacterial cell membranes, resulting in ~3 times higher in vivo BL activity in bacterial cells than with firefly luciferin. Overall, this is the brightest FR emitting combination ever reported, and is very promising for bioimaging purposes in mammalian tissues.
Scientific journal, English

Bright near-infrared chemiluminescent dyes: Phthalhydrazides conjugated with fluorescent BODIPYs
Guanglei Li; Takashi Hirano; Koji Yamada
Dyes and Pigments, Elsevier BV, 178, 108339-108339, Jul. 2020, Peer-reviwed, True, A series of phthalhydrazides conjugated with NIR fluorescent BODIPY dyes were synthesized (three steps, overall yields 68–83%) and found to show strong NIR chemiluminescence (CL) with maxima in the range of 670–736 nm. One of these showed a CL quantum yield reaching 8.4 times higher than that of luminol. Tuning of the fluorescence band of the BODIPY unit directly leads to a red-shifted CL, developing a strategy for designing NIR chemiluminogens.
Scientific journal, English

Development of near‐infrared firefly luciferin analogue reacted with wild‐type and mutant luciferases
Nobuo Kitada; Ryohei Saito; Rika Obata; Satoshi Iwano; Kazuma Karube; Atsushi Miyawaki; Takashi Hirano; Shojiro A. Maki
Chirality, Wiley, 32, 7, 922-931, 04 May 2020, Peer-reviwed, Invited, True, Interestingly, only the D-form of firefly luciferin produces light by luciferin–luciferase (L–L) reaction. Certain firefly luciferin analogues with modified structures maintain bioluminescence (BL) activity; however, all L-form luciferin analogues show no BL activity. To this date, our group has developed luciferin analogues with moderate BL activity that produce light of various wavelengths. For in vivo bioluminescence imaging, one of the important factors for detection sensitivity is tissue permeability of the number of photons emitted by L–L reaction, and the wavelengths of light in the near-infrared (NIR) range (700–900 nm) are most appropriate for the purpose. Some NIR luciferin analogues by us had performance for in vivo experiments to make it possible to detect photons from deep target tissues in mice with high sensitivity, whereas only a few of them can produce NIR light by the L–L reactions with wild-type luciferase and/or mutant luciferase. Based on the structure–activity relationships, we designed and synthesized here a luciferin analogue with the 5-allyl-6-dimethylamino-2-naphthylethenyl moiety. This analogue exhibited NIR BL emissions with wild-type luciferase (λmax = 705 nm) and mutant luciferase AlaLuc (λmax = 655 nm).
Scientific journal, English

Isomeric difference in the crystalline-state chemiluminescence property of an adamantylideneadamantane 1,2-dioxetane with a phthalimide chromophore
Chihiro Matsuhashi; Takuya Ueno; Hidehiro Uekusa; Ayana Sato-Tomita; Kouhei Ichiyanagi; Shojiro Maki; Takashi Hirano
Corresponding, Chemical Communications, Royal Society of Chemistry (RSC), 56, 23, 3369-3372, Mar. 2020, Peer-reviwed, True, Syn- and anti-isomers of an adamantylideneadamantane 1,2-dioxetane having a phthalimide side chain were prepared and investigated their crystalline-state chemiluminescence (CL) properties. The isomers showed contrastive CL properties depending on their crystal-structural characteristics, indicating that CL provides an attractive target for real-time monitoring of a chemical reaction in the crystal.
Scientific journal, English

Phrixotrix luciferase and 6’-aminoluciferins reveal a larger luciferin phenolate binding site and provide novel far-red combinations for bioimaging purposes
Bevilaqua, V. R; Matsuhashi, T; Oliveira, G; Oliveira; P. S. L; Hirano, T; Viviani, V. R
Scientific Reports, Splinger Nature, 9, 8998-17 pages, 21 Jun. 2019, Peer-reviwed, True, with international co-author(s), How the unique luciferase of Phrixothrix hirtus (PxRE) railroad worm catalyzes the emission of red bioluminescence using the same luciferin of fireflies, remains a mystery. Although PxRE luciferase is a very attractive tool for bioanalysis and bioimaging in hemoglobin rich tissues, it displays lower quantum yield (15%) when compared to green emitting luciferases (>40%). To identify which parts of PxRE luciferin binding site (LBS) determine bioluminescence color, and to develop brighter and more red-shifted emitting luciferases, we compared the effects of site-directed mutagenesis and of larger 6′-substituted aminoluciferin analogues (6′-morpholino- and 6′-pyrrolidinyl-LH) on the bioluminescence properties of PxRE and green-yellow emitting beetle luciferases. The effects of mutations in the benzothiazolyl and thiazolyl parts of PxRE LBS on the KM and catalytic efficiencies, indicated their importance for luciferin binding and catalysis. However, the absence of effects on the bioluminescence spectrum indicated a less interactive LBS in PxRE during light emission. Mutations at the bottom of LBS of PxRE blue-shifted the spectra and increased catalytic efficiency, suggesting that lack of interactions of this part of LBS with excited oxyluciferin phenolate underlie red light emission. The much higher bioluminescence activity and red-shifted spectra of PxRE luciferase with 6′-morpholino- (634 nm) and 6′-pyrrolidinyl-luciferins (644 nm), when compared to other beetle luciferases, revealed a larger luciferin phenolate binding pocket. The size and orientation of the side-chains of L/I/H348 are critical for amino-analogues accommodation and modulate bioluminescence color, affecting the interactions and mobility of excited oxyluciferin phenolate. The PxRE luciferase and 6′-aminoluciferins provide potential far-red combinations for bioimaging applications.
Scientific journal, English

Halogen-substituent effect on the spectroscopic properties of 2-phenyl-6-dimethylaminobenzothiazoles
Rena Misawa; Chihiro Matsuhashi; Minoru Yamaji; Toshiki Mutai; Isao Yoshikawa; Hirohiko Houjou; Keiichi Noguchi; Shojiro Maki; Takashi Hirano
Corresponding, Tetrahedron Letters, Elsevier BV, 60, 26, 1702-1705, Jun. 2019, Peer-reviwed, True, 6-Dimethylamino-2-phenylbenzothiazole (1-H) is a push-pull benzothiazole fluorophore mimicking the firefly oxyluciferin structure. We newly prepared 7-chloro and 7-bromo derivatives of 1-H and its 4-acetyl derivative (2-H), and their spectroscopic and photophysical properties were investigated. The halogenated derivatives showed the blue-shifted electronic absorption maxima and fluorescence emission maxima compared to 1-H and 2-H, resulted from the deformations of the NMe2 groups and the electron withdrawing properties of the halogen groups. In addition, the halogen substitutions accelerate intersystem crossing by heavy atom effect, resulting in a decrease in fluorescence quantum yields. Interestingly, however, the halogenated derivatives of 2-H still showed moderate fluorescence quantum yields. The halogenation effect is one of the guides to design push-pull benzothiazole fluorophores for tuning fluorescence properties.
Scientific journal, English

Spectroscopic properties of push-pull 2-(4-carboxyphenyl)-6-dimethylaminobenzothiazole derivatives in solution and the solid state
Yusuke Takahashi; Takuya Uehara; Chihiro Matsuhashi; Minoru Yamaji; Toshiki Mutai; Isao Yoshikawa; Hirohiko Houjou; Kota Kitagawa; Tomoyoshi Suenobu; Shojiro Maki; Takashi Hirano
Corresponding, Journal of Photochemistry and Photobiology A: Chemistry, Elsevier BV, 376, 324-332, May 2019, Peer-reviwed, True, 6-Dimethylamino-2-phenylbenzothiazoles with a carboxy, ester and amide substituent on the 2-phenyl group were prepared as a series of the push-pull benzothiazoles, and their spectroscopic and photophysical properties in solutions were investigated. The derivatives showed solvatochromic fluorescence with quantum yields over 0.68 in various organic solvents similar to the core fluorophore structure. The color variation ranges in fluorescence solvatochromism of the derivatives were wider than that of the original compound having the core structure, 6-dimethylamino-2-phenylbenzothiazole. It was also found that the derivatives together with the original compound show solid state fluorescence depending on their crystal structures. In particular, an ester derivative with a protected serine has a reasonable crystal packing leading to increase in fluorescence efficiency. The results of the present study provide a guide to design push-pull 2-phenylbenzothiazoles exhibiting fluorescence in solution and the solid state.
Scientific journal, English

Synthesis and Luminescence Properties of Near-Infrared N-Heterocyclic Luciferin Analogues for In Vivo Optical Imaging
Ryohei Saito; Takahiro Kuchimaru; Shoko Higashi; Shijia W. Lu; Masahiro Kiyama; Satoshi Iwano; Rika Obata; Takashi Hirano; Shinae Kizaka-Kondoh; Shojiro A. Maki
Bulletin of the Chemical Society of Japan, The Chemical Society of Japan, 92, 3, 608-618, 15 Mar. 2019, Peer-reviwed, True, As a means of achieving highly sensitive bioluminescence imaging of deep tissues utilizing the firefly luciferin-luciferase (L-L) reaction, we previously reported a luciferin analogue, AkaLumine, which exhibits high cell-permeability and emits near-infrared (NIR) light with high tissue-penetration by the L-L reaction. However, while AkaLumine enables us to observe targets in deep tissues, its poor solubility in aqueous media limits its utility for in vivo imaging. Herein, to address this issue, we have synthesized three AkaLumine derivatives with N-heterocyclic aromatic rings as new red luciferin analogues that have substantially higher solubility than that of AkaLumine in phosphate buffered saline solution. One of the derivatives (herein termed seMpai) exhibits an emission maximum at 675 nm upon L-L reaction with Photinus pyralis luciferase and presents an activity in mouse-tissue imaging similar to that of AkaLumine. It is hoped that seMpai will extend the application of high-sensitivity NIR bioluminescence imaging in a wide range of biomedical research fields.
Scientific journal, English

The proton and metal binding sites responsible for the pH-dependent green-red bioluminescence color tuning in firefly luciferases
Vadim R. Viviani; Gabriele V. M. Gabriel; Vanessa R. Bevilaqua; A. F. Simões; T. Hirano; P. S. Lopes-de-Oliveira
Scientific Reports, Springer Science and Business Media LLC, 8, 1, 17594, 04 Dec. 2018, Peer-reviwed, Firefly luciferases produce yellow-green light under physiological and alkaline conditions, however at acidic pH, higher temperatures or in the presence of heavy metals the color changes to red, a property called pH-sensitivity. Despite many decades of studies, the proton and metal binding sites responsible for pH-sensitivity remain enigmatic. Previously we suggested that the salt bridge E311/R337 keeps a closed conformation of the luciferin phenolate binding site. Here we further investigated the effect of this salt bridge and mutations of the neighbor residues H310 and E/N354, on metal and pH-sensitivity of firefly luciferases emitting distinct bioluminescence colors (Cratomorphus distinctus: 548 nm; Macrolampis sp2: 569 nm). The substitutions of H310 and E/N354 modulate metal sensitivity, whereas the carboxylate of E311 may work as the catalytic base essential for green bioluminescence and pH-sensitivity. Modeling studies showed that H310, E311 and E354 side-chains coordinate Zinc, constituting the metal binding site and the pH-sensor. Electrostatic potential and pKa calculations suggest that the external couple H310/E354 is affected by pH, whereas E311/R337 make a stabilized internal pair which retains excited oxyluciferin ejected proton near its phenolate group into a high energy state, promoting yellow-green bioluminescence. Protonation or metal binding weaken these electrostatic gates and their ability to retain the excited oxyluciferin released proton near its phenolate, promoting red light emission.
Scientific journal, English

Structure-fluorescence relationship of push-pull 2-phenylbenzothiazole derivatives designed based on the firefly light-emitter
Tomoya Fujikawa; Takuya Uehara; Minoru Yamaji; Takuya Kanetomo; Takayuki Ishida; Shojiro Maki; Takashi Hirano
Corresponding, Tetrahedron Letters, Elsevier Ltd, 59, 14, 1431-1434, 04 Apr. 2018, Peer-reviwed, True, 6-Dimethylamino-2-phenylbenzothiazole (1a) mimicking the firefly oxyluciferin structure and the derivatives with an electron-withdrawing substituent on the phenyl group were prepared, and their fluorescence properties were investigated in various solvents. 1a showed solvatochromic fluorescence with good fluorescence quantum yields (Φf >0.8). The introduction of an electron-withdrawing group led to a red-shift of the emission maximum. In particular, the derivatives with the 2,2-dicyanoethenyl and (1,3-dihydro-1,3-dioxo-2H-inden-2-ylidene)methyl groups showed near-infrared fluorescence in chloroform. In addition, the derivative with the phenylimine moiety showed efficient solid-state fluorescence, resulted from a molecular arrangement inhibiting intermolecular interactions for quenching the fluorescence state in crystals.
Scientific journal, English

Toward bioluminescence in the near-infrared region: Tuning the emission wavelength of firefly luciferin analogues by allyl substitution
Nobuo Kitada; Tsuyoshi Saitoh; Yuma Ikeda; Satoshi Iwano; Rika Obata; Haruki Niwa; Takashi Hirano; Atsushi Miyawaki; Koji Suzuki; Shigeru Nishiyama; Shojiro A. Maki
Tetrahedron Letters, Elsevier Ltd, 59, 12, 1087-1090, 21 Mar. 2018, Peer-reviwed, True, The synthesis and bioluminescence of allyl-substituted luciferin derivatives as substrates for firefly luciferase are reported. The allylation of luciferins induced bathochromic shift (15–40 nm) of the bioluminescence emission. Upon combination with other chemical modifications for bioluminescence wavelength tuning, novel red emitting luciferin analogues were obtained with emission maxima at 685 and 690 nm.
Scientific journal, English

Quantum yield improvement of red-light-emitting firefly luciferin analogues for in vivo bioluminescence imaging
Masahiro Kiyama; Satoshi Iwano; Satoshi Otsuka; Shijia W. Lu; Rika Obata; Atsushi Miyawaki; Takashi Hirano; Shojiro A. Maki
Tetrahedron, Elsevier Ltd, 74, 6, 652-660, 08 Feb. 2018, Peer-reviwed, True, The dimethylamino group of AkaLumine ((4S)-2-[ (1E,3E)-4-[4-(dimethylamino)phenyl]-1,3-butadien-1-yl]-4,5-dihydro-4-thiazolecarboxylic acid), a red-light-emitting firefly luciferin analogue, was replaced by cyclic amino groups (1-pyrrolidinyl, 1-piperidino, 1-azepanyl, and 4-morpholino) to give AkaLumine analogues exhibiting desirable bioluminescence with emission maxima in the red region (656–667 nm). In particular, a bioluminescence reaction of 1-pyrrolidinyl analogue with a recombinant Photinus pyralis luciferase showed a higher quantum yield than that with AkaLumine, giving an improved bioluminescence intensity. The 1-pyrrolidinyl analogue also showed the strongest luminescence in whole-body luciferase-expressing mice among the analogues, indicating that a quantum yield improvement of a luciferin analogue is effective to increase bioluminescence imaging intensity.
Scientific journal, English

Electronic and Steric Effects of Cyclic Amino Substituents of Luciferin Analogues on a Firefly Luciferin-Luciferase Reaction
Michio Kakiuchi; Soichiro Ito; Masahiro Kiyama; Fumiya Goto; Takuto Matsuhashi; Minoru Yamaji; Shojiro Maki; Takashi Hirano
Corresponding, Chemistry Letters, The Chemical Society of Japan, 46, 8, 1090-1092, Aug. 2017, Peer-reviwed, True, Bioluminescent and spectroscopic properties of luciferin analogues with cyclic amino substituents (1-pyrrolidinyl, piperidino, 1-azepanyl, and morpholino groups) at the 6' position were investigated by comparing with those of 6'-dimethylaminoluciferin, to provide information on spatial and molecular environmental properties of the active site in Photinus pyralis luciferase.
Scientific journal, English

Spectroscopic Properties of Amine-substituted Analogues of Firefly Luciferin and Oxyluciferin
Michio Kakiuchi; Soichiro Ito; Minoru Yamaji; Vadim R. Viviani; Shojiro Maki; Takashi Hirano
Corresponding, Photochemistry and Photobiology, Wiley, 93, 2, 486-494, 16 Dec. 2016, Peer-reviwed, True, Spectroscopic and photophysical properties of firefly luciferin and oxyluciferin analogues with an amine substituent (NH2, NHMe and NMe2) at the C6' position were studied based on absorption and fluorescence measurements. Their π-electronic properties were investigated by DFT and TD-DFT calculations. These compounds showed fluorescence solvatochromism with good quantum yields. An increase in the electron-donating strength of the substituent led to the bathochromic shift of the fluorescence maximum. The fluorescence maxima of the luciferin analogues and the corresponding oxyluciferin analogues in a solvent were well correlated with each other. Based on the obtained data, the polarity of a luciferase active site was explained. As a result, the maximum wavelength of bioluminescence for a luciferin analogue was readily predicted by measuring the photoluminescence of the luciferin analogue in place of that of the corresponding oxyluciferin analogue.
Scientific journal, English

Spectroscopic properties of BF2 complexes of N-(5-phenyl-2-pyrazinyl) pivalamides exhibiting fluorescence in solution and solid state
Sojiro Hachiya; Daisuke Hashizume; Hiroshi Ikeda; Minoru Yamaji; Shojiro Maki; Haruki Niwa; Takashi Hirano
Corresponding, Journal of Photochemistry and Photobiology A-Chemistry, ELSEVIER SCIENCE SA, 331, 206-214, Dec. 2016, Peer-reviwed, Invited, True, Boron difluoride (BF2) complexes of N-(5-phenyl-2-pyrazinyl)pivalamide and its derivatives having a substituent on the phenyl group were prepared and their spectroscopic properties were investigated. It was found that the BF2 complexes show fluorescence in solution and the solid state. The origins of the fluorescence properties are discussed on the basis of the fluorescence yields and lifetimes, crystal structures and DFT calculations. The present work would provide a guide to design BF2 complexes of amidopyrazines exhibiting solid state fluorescence.
Scientific journal, English

Glu311 and Arg337 Stabilize a Closed Active-site Conformation and Provide a Critical Catalytic Base and Countercation for Green Bioluminescence in Beetle Luciferases
V. R. Viviani; A. Simões; V. R. Bevilaqua; G. V. M. Gabriel; F. G. C. Arnoldi; T. Hirano
Biochemistry, American Chemical Society (ACS), 55, 34, 4764-4776, 18 Aug. 2016, Peer-reviwed, True, Beetle luciferases elicit the emission of different bioluminescence colors from green to red. Whereas firefly luciferases emit yellow-green light and are pH-sensitive, undergoing a typical red-shift at acidic pH and higher temperatures and in the presence of divalent heavy metals, click beetle and railroadworm luciferases emit a wider range of colors from green to red but are pH-independent. Despite many decades of study, the structural determinants and mechanisms of bioluminescence colors and pH sensitivity remain enigmatic. Here, through modeling studies, site-directed mutagenesis, and spectral and kinetic studies using recombinant luciferases from the three main families of bioluminescent beetles that emit different colors of light (Macrolampis sp2 firefly, Phrixotrix hirtus railroadworm, and Pyrearinus termitilluminans click beetle), we investigated the role of E311 and R337 in bioluminescence color determination. All mutations of these residues in firefly luciferase produced red mutants, indicating that the preservation of opposite charges and the lengths of the side chains of E311 and R337 are essential for keeping a salt bridge that stabilizes a closed hydrophobic conformation favorable for green light emission. Kinetic studies indicate that residue R337 is important for binding luciferin and creating a positively charged environment around excited oxyluciferin phenolate. In Pyrearinus green-emitting luciferase, the R334A mutation causes a 27 nm red-shift, whereas in Phrixotrix red-emitting luciferase, the L334R mutation causes a blue-shift that is no longer affected by guanidine. These results provide compelling evidence that the presence of arginine at position 334 is essential for blue-shifting the emission spectra of most beetle luciferases. Therefore, residues E311 and R337 play both structural and catalytic roles in bioluminescence color determination, by stabilizing a closed hydrophobic conformation favorable for green light emission, and also providing a base to accept excited oxyluciferin phenol proton, and a countercation to shield the negative charge of E311 and to stabilize excited oxyluciferin phenolate, blue-shifting emission spectra in most beetle luciferases.
Scientific journal, English

Enhanced brightness of 2,6-diphenylthiazolo[4,5-b]pyrazines by introducing double electron donating groups
Yoshihisa Suzuki; Minoru Yarnaji; Shojiro Maki; Takashi Hirano
Journal of Photochemistry and Photobiology A-Chemistry, ELSEVIER SCIENCE SA, 314, 93-95, Jan. 2016, Peer-reviwed, True, Thiazolo[4,5-b]pyrazine (TPy) derivatives with enhanced fluorescence brightness were developed by tuning the double substituents. The spectroscopic and photophysical properties were investigated by measurements of absorption and fluorescence spectra, fluorescence yields and lifetimes. Based on the DFT calculations, the increased brightness was rationalized by the enhanced electronic absorptivity and fluorescence yields. The developed methodology provides the guide to design high-performance TPy fluorophores.
Scientific journal, English

Molecular Origin of Color Variation in Firefly (Beetle) Bioluminescence: A Chemical Basis for Biological Imaging
Takashi Hirano
Lead, Current Topics in Medicinal Chemistry, BENTHAM SCIENCE PUBL LTD, 16, 24, 2638-2647, 2016, Peer-reviwed, Invited, True, Firefly shows bioluminescence by “luciferin−luciferase” (L−L) reaction using luciferin, luciferase, ATP and O2. The chemical photon generation by an enzymatic reaction is widely utilized for analytical methods including biological imaging in the life science fields. To expand photondetecting analyses with firefly bioluminescence, it is important for users to understand the chemical basis of the L−L reaction. In particular, the emission color variation of the L−L reaction is one of the distinguishing characteristics for multicolor luciferase assay and in vivo imaging. From the viewpoint of fundamental chemistry, this review explains the recent progress in the studies on the molecular mechanism of emission color variation after showing the outline of the reaction mechanism of the whole L−L reaction. On the basis of the mechanism, the progresses in organic synthesis of luciferin analogs modulating their emission colors are also presented to support further developments of red/near infrared in vivo biological imaging utility of firefly bioluminescence.
Scientific journal, English

Fluorescence Properties of Diphenylthiazolo[4,5-b]pyrazines Tuned by Donor-Acceptor Substituent Effects
Tatsuki Nakagawa; Minoru Yamaji; Shojiro Maki; Haruki Niwa; Takashi Hirano
Photochemistry and Photobiology, WILEY-BLACKWELL, 91, 4, 807-813, Jul. 2015, Peer-reviwed, True, Fluorescence properties of 2,6- and 2,5-diphenylthiazolo[4,5-b]pyrazine (TPy) derivatives having an electron-donating substituent (methoxy and dimethylamino) on the 6- and 5-phenyl groups were studied. It was found that 2,6-diphenyl derivatives fluoresce more efficiently than 2,5-diphenyl derivatives. Furthermore, a 2,6-diphenyl derivative having an additional cyano group on the 2-phenyl ring was an excellent fluorophore showing a wide solvatochromism with great fluorescence yields. Based on the obtained spectroscopic data and mechanistic explanations concerning the substituent effects on the fluorescence properties, useful information on designing new TPy fluorophores is provided. Fluorescence properties of 2,6- and 2,5-diphenylthiazolo[4,5-b]pyrazines having an electron-donating substituent (methoxy and dimethylamino) on the 6- and 5-phenyl groups were studied. Furthermore, 2,6-diphenyl derivatives having an additional cyano group on the 2-phenyl ring were developed, to give an excellent fluorophore.
Scientific journal, English

Substituent effects on fluorescence properties of thiazolo[4,5-b]pyrazine derivatives
Tatsuki Nakagawa; Minoru Yamaji; Shojiro Maki; Haruki Niwa; Takashi Hirano
Corresponding, Photochemical & Photobiological Sciences, ROYAL SOC CHEMISTRY, 13, 12, 1765-1772, Dec. 2014, Peer-reviwed, True, Based on spectroscopic measurements and DFT calculations, fluorescence properties of thiazolo[4,5-b]-pyrazine (TPy) derivatives with the phenyl group at the C2 position were studied. TPys were readily prepared from the corresponding amidopyrazines, which have a similar fluorescent core to a bioluminescence light emitter, Cypridina oxyluciferin. It was found that the introduction of electron-donating (methoxy and dimethylamino) groups onto the 2-phenyl moiety of the TPy derivatives, as well as the phenyl and 4-(dimethylamino) phenyl groups at C2 and C6, respectively, increases the fluorescence yield and appearance of solvatochromic character. The mechanism of increasing the fluorescence yield depending on the substituents is discussed. These findings provide useful information on designing new TPy fluorophores.
Scientific journal, English

Synthesis and chemiluminescent properties of 6,8-diaryl-2-methylimidazo[1,2-alpha]pyrazin-3(7H)-ones: Systematic investigation of substituent effect at para-position of phenyl group at 8-position
Ryota Saito; Takashi Hirano; Shojiro Maki; Haruki Niwa
Journal of Photochemistry and Photobiology A-Chemistry, ELSEVIER SCIENCE SA, 293, 12-25, Nov. 2014, Peer-reviwed, True, 6,8-Diphenylimidazopyrazinone derivatives having a substituent R (R=CF3, H, and OMe) at pare position of the 8-phenyl group were synthesized and their chemiluminescent properties were investigated. The chemiluminescence maxima (CLmax) of these compounds were observed to be in the range of 513-553 nm with a bathochromic shift that increased with the electron-withdrawing character of R, contrary to the previously observed substituent effect at the 6-postion. The chemiluminescence efficiencies (phi(CL)) of these imidazopyrazinones were improved by the introduction of a p-substituted phenyl group at the 8-position. The quantitative investigation of the three quantum efficiencies (phi(R), phi(S), and phi(FL)) whose product gives us phi(CL) revealed that the phi(CL) gains made were largely because of the increase in the values of the fluorescence quantum yields of the corresponding light emitters (phi(FL)). The yields of the singlet-excited emitters (phi(S)) during the chemiluminescent reaction were found to be very small (0.015-0.019), suggesting that one cannot construct an efficient imidazopyrazinone-chemiluminescence system that is comparable to the aequorin bioluminescence system only by using the electronic effects of substituents. (C) 2014 Elsevier B.V. All rights reserved.
Scientific journal, English

Bioluminescence of Beetle Luciferases with 6 '-Amino-D-luciferin Analogues Reveals Excited Keto-oxyluciferin as the Emitter and Phenolate/Luciferin Binding Site Interactions Modulate Bioluminescence Colors
Vadim R. Viviani; Deimison Rodrigues Neves; Danilo Trabuco Amaral; Rogilene A. Prado; Takuto Matsuhashi; Takashi Hirano
Biochemistry, AMER CHEMICAL SOC, 53, 32, 5208-5220, Aug. 2014, Peer-reviwed, True, with international co-author(s), Beetle luciferases produce different bioluminescence colors from green to red using the same D-luciferin substrate. Despite many studies of the mechanisms and structural determinants of bioluminescence colors with firefly luciferases, the identity of the emitters and the specific active site interactions responsible for bioluminescence color modulation remain elusive. To address these questions, we analyzed the bioluminescence spectra with 6'-amino-D-luciferin (aminoluciferin) and its 5,5-dimethyl analogue using a set of recombinant beetle luciferases that naturally elicit different colors and different pH sensitivities (pH-sensitive, Amydetes vivianii lambda(max) = 538 nm, Macrolampis sp(2) lambda(max) = 564 nm; pH-insensitive, Phrixotrix hirtus lambda(max) = 623 nm, Phrixotrix vivianii lambda(max) = 546 nm, and Pyrearinus termitilluminans lambda(max) = 534 nm), a luciferase-like enzyme (Tenebrionidae, Zophobas mono lambda(max) = 613 nm), and mutants of C311 (S314). The green-yellow-emitting luciferases display red-shifted bioluminescence spectra with aminoluciferin in relation to those with D-luciferin, whereas the red-emitting luciferases displayed blue-shifted spectra. Bioluminescence spectra with 5,5-dimethylaminoluciferin, in which enolization is blocked, were almost identical to those of aminoluciferin. Fluorescence probing using 2-(4-toluidino)naphthalene-6-sulfonate and inference with aminoluciferin confirm that the luciferin binding site of the red-shifted luciferases is more polar than in the case of the green-yellow-emitting luciferases. Altogether, the results show that the keto form of excited oxyluciferin is the emitter in beetle bioluminescence and that bioluminescence colors are essentially modulated by interactions of the 6'-hydroxy group of oxyluciferin and basic moieties under the influence of the microenvironment polarity of the active site: a strong interaction between a base moiety and oxyluciferin phenol in a hydrophobic microenvironment promotes green-yellow emission, whereas a more polar environment weakens such interaction promoting red shifts. In pH-sensitive luciferases, a pH-mediated switch from a closed hydrophobic conformation to a more open polar conformation promotes the typical red shift.
Scientific journal, English

Chemiluminescent 2,6-diphenylimidazo[1,2-a]pyrazin-3(7H)-ones: a new entry to Cypridina luciferin analogues
Yuki Ishii; Chihiro Hayashi; Yoshihisa Suzuki; Takashi Hirano
Corresponding, Photochemical & Photobiological Sciences, ROYAL SOC CHEMISTRY, 13, 2, 182-189, Feb. 2014, Peer-reviwed, True, An investigation of the chemiluminescent properties of 2,6-diphenylimidazo[1,2-a]pyrazin-3(7H)-one derivatives (1), having substituted phenyl groups, is described. Among the derivatives 1, the 6-[4-(dimethylamino) phenyl] derivatives (1a,d-f) gave a high quantum yield (Phi(CL) >= 0.0025) in diglyme/acetate buffer, which is a model reaction condition for the Cypridina bioluminescence. Their efficient chemiluminescence is mainly caused by the electronic effect of the substituent at C6. In particular, the electrondonating 4-(dimethylamino)phenyl group at C6 of 1a,d-f plays an essential role in increasing the chemi-excitation efficiency (Phi(S)) by the charge transfer-induced luminescence (CTIL) mechanism. The results provide useful information for designing new Cypridina luciferin analogues showing efficient chemiluminescence.
Scientific journal, English

Synthesis and luminescence properties of biphenyl-type firefly luciferin analogs with a new, near-infrared light-emitting bioluminophore
Chihiro Miura; Masahiro Kiyama; Satoshi Iwano; Kazuto Ito; Rika Obata; Takashi Hirano; Shojiro Maki; Haruki Niwa
Tetrahedron, PERGAMON-ELSEVIER SCIENCE LTD, 69, 46, 9726-9734, Nov. 2013, Peer-reviwed, True, New firefly luciferin analogs of the 4,4 '-substituted biphenyl-type were synthesized. One analog with a 4 '-dimethylamino group possessed bioluminescence activity, emitting near-infrared biological window light at 675 nm suitable for deep-site bioimaging of living animals. The chemiluminescence light-emission maximum of the corresponding methyl ester of the bioluminescence active analog was 500 nm, implying that biphenyl and thiazolinone rings in the light emitter might be placed in a coplanar conformation at the polar luciferase active site. (c) 2013 Elsevier Ltd. All rights reserved.
Scientific journal, English

Development of simple firefly luciferin analogs emitting blue, green, red, and near-infrared biological window light
Satoshi Iwano; Rika Obata; Chihiro Miura; Masahiro Kiyama; Kazutoshi Hama; Mitsuhiro Nakamura; Yoshiharu Amano; Satoshi Kojima; Takashi Hirano; Shojiro Maki; Haruki Niwa
Tetrahedron, Elsevier, 69, 19, 3847-3856, 13 May 2013, Peer-reviwed, Simple firefly luciferin analogs emitting blue, green, and red light were developed. The longest emission maximum was observed at 675 nm, which belongs to the NIR biological window (650-900 nm), useful for deep site bioimaging of living animals. The analogs showed a slow rise of emission intensity compared with the rapid emission of natural luciferin. The light emission of the adenylated analogs was strongly enhanced compared with those of analogs themselves.© 2013 Elsevier Ltd. All rights reserved.
Scientific journal, English

Evaluation of Bioluminescence Activity of Firefly Luciferin Nucleotide Derivatives
Satoshi IWANO; Satoshi KOJIMA; Takashi HIRANO; Shojiro MAKI; Haruki NIWA
ECS Transactions, The Electrochemical society, 50, 29, 1-3, 2013, Peer-reviwed, True, We study firefly bioluminescence to create practical bio imaging tool. Firefly bioluminescence has two serious problems; color and brightness control. We give solutions; archive multi-color emission (430 ~ 680 nm) and Emission Enhancing Technology (EET, 1000 fold brightness than wild type). But these solutions are not enough as practical use because of low brightness (multicolor) and low stability (EET). In this study, we focused on lumenscent intensity, in fact improvement of EET was done for create practical imaging tool.
Scientific journal, English

5-[4-(Dimethylamino)phenyl]-2-benzamidopyrazines: fluorescent dyes based on Cypridina oxyluciferin
Takashi Hirano; Tatsuki Nakagawa; Ai Kodaka; Shojiro Maki; Haruki Niwa; Minoru Yamaji
Lead, Research on Chemical Intermediates, SPRINGER, 39, 1, 233-245, Jan. 2013, Peer-reviwed, True, To clarify the acyl substitution effect on the fluorescent property of Cypridina oxyluciferin analogs, which have the 4-(dimethylamino)phenyl group at C5, we compared the spectroscopic properties of benzamide 1b and its 2,6-dimethylphenyl derivative 1c in various solvents with those of acetamide 1a. Similarity of the fluorescence wavelengths of 1a-c indicates that the pi-electronic conjugation in the excited singlet (S-1) state is terminated at the acyl group and that the benzamide moiety in 1b has little effect on modulating the florescence color. The similar fluorescence solvatochromism of 1a-c reveals that their S-1 states have a similar intramolecular charge transfer character. The fact that 1a-c have various fluorescence quantum yields and lifetimes depending on solvent polarity and hydrogen bonding interactions in solutions provides information about the decay processes competing with the fluorescence process in the S-1 states. Among 1a-c, benzamide 1b exhibits the most sensitive variation of the fluorescence intensity depending on the solvent used. Similarity of the fluorescence spectra of 1a-c adsorbed in NaY zeolites was also observed, which indicates that the S-1 states of 1a-c give mobile conformers in the NaY supercages. The relationship between the molecular structures of 1a-c and their spectroscopic properties will provide a guide for designing a new fluorophore based on Cypridina oxyluciferin.
Scientific journal, English

Spectroscopic studies of the color modulation mechanism of firefly (beetle) bioluminescence with amino-analogs of luciferin and oxyluciferin
Takashi Hirano; Hiroyuki Nagai; Takuto Matsuhashi; Yosuke Hasumi; Satoshi Iwano; Kazuto Ito; Shojiro Maki; Haruki Niwa; Vadim R. Viviani
Lead, Photochemical and Photobiological Sciences, Royal Society of Chemistry, 11, 8, 1281-1284, Aug. 2012, Peer-reviwed, True, with international co-author(s), Spectroscopic properties of amino-analogs of luciferin and oxyluciferin were investigated to confirm the color modulation mechanism of firefly (beetle) bioluminescence. Fluorescence solvatochromic character of aminooxyluciferin analogs indicates that the bioluminescence of aminoluciferin is useful for evaluating the polarity of a luciferase active site. © 2012 The Royal Society of Chemistry and Owner Societies.
Scientific journal, English

Studies on (-)ESI-MS/MS of a glycosaminoglycan disaccharide N-acetyllactosamine-6,6 '-disulfate disodium salt-Charge-localization isomers
Yoko Ohashi; Masayuki Kubota; Hiroshi Hatase; Takashi Hirano; Shojiro Maki; Haruki Niwa
International Journal of Mass Spectrometry, ELSEVIER SCIENCE BV, 312, 179-184, Feb. 2012, Peer-reviwed, True, We previously reported the ESI-MS/MS studies on distinguishing Gal beta 1-4GlcNAc-6,6'-disulfate disodium salt from 2'-epimer,(1) namely Gal beta 1-4ManNAc-6,6'-disulfate [1]. Here, we must emphasize first that distinction of the epimeric pair was successful using either FAB or MALDI, but most effectively done by ESI mass spectrometry. However, though totally independent of our original aim of distinguishing epimers, we later realized that there were some inaccuracies in our assignment of the fragmentation path of negative product ions. Through our intensive studies to establish the right fragmentation path, we now propose a new concept of isomers caused by the difference in the localization of a negative charge in apparently the same MS1 ion of a disaccharide dibasic acid. (C) 2011 Elsevier B.V. All rights reserved.
Scientific journal, English

Bioluminescence characteristics of the fruiting body of Mycena chlorophos
Kenichi Mori; Satoshi Kojima; Shojiro Maki; Takashi Hirano; Haruki Niwa
Luminescence, WILEY-BLACKWELL, 26, 6, 604-610, Nov. 2011, Peer-reviwed, True, Bioluminescent fungi are widely distributed on land and most belong to the class Basidomycetes. Light of about 530 nm wavelength maximum is emitted continuously. The molecular basis for the light-emitting process remains unclear. We investigated the characteristics of the bioluminescence using cultivated fruiting bodies of M. chlorophos. Only fresh fruiting bodies exhibited long-lasting light emission; rapid decay of light emission was observed with frozen and freeze-dried samples. Freeze-dried samples can be stored at room temperature under dry conditions and may be useful for the isolation of luciferin. The light emission of the fresh fruiting bodies was maintained in various buffers at varying pH; it could be stopped with pH 4 acetate buffer and could be recovered at pH 6. The isolation of luciferin from the fresh fruiting bodies might be possible by the control of buffer pH. The effect of temperature on the light emission of fruiting bodies indicated that bioluminescence in M. chlorophos may involve enzymatic reaction(s). The solubilization of bioluminescent components from the fruiting bodies could not be achieved with various surfactants. Copyright (C) 2011 John Wiley & Sons, Ltd.
Scientific journal, English

Influence of electron-donating and electron-withdrawing substituents on the Chemiluminescence behavior of Coelenterazine analogs
Ryota Saito; Takashi Hirano; Shojiro Maki; Haruki Niwa; Mamoru Ohashi
Bulletin of the Chemical Society of Japan, The Chemical Society of Japan, 84, 1, 90-99, Jan. 2011, Peer-reviwed, True, Coelenterazine analogs 3a3e possessing various substituents at the para-position of the 6-phenyl group (R = CF3, F, H, OMe, and NMe 2) were synthesized, and the chemiluminescent properties of 3a3e in dimethyl sulfoxide (DMSO) were investigated quantitatively. Chemiluminescence maxima observed in the range of 454478nm showed a bathochromic shift as the electron-donating ability of R increased. Chemiluminescence quantum yields (φCL) were obtained in the range of 0.00060.0018. The analog 3a possessing the electron-withdrawing CF3 group showed a slight decrease in its φCL value. The fluorescence quantum yields (φF) of the light emitter, 2-acetamidopyrazine anions 4a --4e- , were observed in the range of 0.0050.21 and showed substituent dependency in that the increment in the electronwithdrawing ability of R decreases the φF value. The efficiency of generation of the singlet-excited 4a--4e- (φS) showed a small change in the range of 0.0080.015. From these quantitative analyses of the quantum efficiencies, we found that an electron-donating substituent R is not required for the efficient generation of a singlet-excited light emitter, but is required for the high φF of the emitter. © 2011 The Chemical Society of Japan.
Scientific journal, English

Colorimetric and fluorometric sensing of the Lewis acidity of a metal ion by metal-ion complexation of imidazo[1,2-a]pyrazin-3(7H)-ones
Takashi Hirano; Takashi Sekiguchi; Daisuke Hashizume; Hiroshi Ikeda; Shojiro Maki; Haruki Niwa
Lead, Tetrahedron, PERGAMON-ELSEVIER SCIENCE LTD, 66, 21, 3842-3848, May 2010, Peer-reviwed, True, Metal-ion complexation of 7-benzylimidazo[1,2-a]pyrazin-3(7H)-one derivative (2) with Li+, Mg2+, Ca2+, Ba2+, Sc3+, and La3+ in acetonitrile resulted in successive modulations of its UV/vis absorption and fluorescence spectroscopic properties. This result indicates that 2 can be used as a calorimetric and fluorometric sensor of the Lewis acidity of a metal ion in aprotic solutions. The hypothesis that the metal-ion complex has a O10(imidazopyrazinone)-metal ion bond was supported by X-ray crystallographic analysis and quantum chemical calculations for a Li+ complex of 7-methylimidazo[1,2-a]pyrazin-3(7H)-one derivative (1). (C) 2010 Elsevier Ltd. All rights reserved.
Scientific journal, English

Color modulation mechanism of firefly (beetle) bioluminescence based on photochemistry
Takashi Hirano; Yosuke Hasumi; Kazuhiro Ohtsuka; Shojiro Maki; Haruki Niwa; Minoru Yamaji; Daisuke Hashizume
Luminescence, JOHN WILEY & SONS LTD, 25, 2, 97-98, Apr. 2010, Peer-reviwed, True
International conference proceedings, English

Synthesis and properties of bis(pyrazino[2 ',3 ':4,5]imidazole)-fused 1,2,5,6-tetrahydro-1,4,5,8,9,10-hexaazaanthracenes: a new fluorescent nitrogen-rich heterocycle
Sojiro Hachiya; Daisuke Hashizume; Shojiro Maki; Haruki Niwa; Takashi Hirano
Corresponding, Tetrahedron Letters, PERGAMON-ELSEVIER SCIENCE LTD, 51, 10, 1401-1403, Mar. 2010, Peer-reviwed, True, Nitrogen-rich heterocycles, bis(pyrazino[2',3':4,5]imidazole)-fused 1,2,5,6-tetrahydro-1,4,5,8,9,10-hexaazaanthracenes (BPI-HAAs) were prepared by conventional Pd(OAc)(2)/BINAP-catalyzed C-N coupling reactions of 5-aryl-3-bromoaminopyrazines. The BPI-HAA core is a planar structure with aromaticity, and this heterocycle exhibits red fluorescence and moderate electron-accepting characteristics. (C) 2010 Elsevier Ltd. All rights reserved.
Scientific journal, English

Synthesis and fluorescence properties of difluoro[amidopyrazinato-O,N]boron derivatives: a new boron-containing fluorophore
Sojiro Hachiya; Takayuki Inagaki; Daisuke Hashizume; Shojiro Maki; Haruki Niwa; Takashi Hirano
Corresponding, Tetrahedron Letters, PERGAMON-ELSEVIER SCIENCE LTD, 51, 12, 1613-1615, Mar. 2010, Peer-reviwed, True, New boron-containing fluorophores, difluoro[amidopyrazinato-O,N]boron (APB) derivatives, were prepared from amidopyrazines. The fluorescence properties of APB were successfully modulated by an aryl substitution at the C8 position. (C) 2010 Elsevier Ltd. All rights reserved.
Scientific journal, English

Distinction of Sialyl Anomers on ESI- and FAB-MS/MS: Stereo-Specific Fragmentations
Yoko Ohashi; Masayuki Kubota; Hiroshi Hatase; Mitsuhiro Nakamura; Takashi Hirano; Haruki Niwa; Yoshitaka Nagai
Journal of the American Society for Mass Spectrometry, ELSEVIER SCIENCE INC, 20, 3, 394-397, Mar. 2009, Peer-reviwed, True, An anomeric pair of the lysoglyceroganglioside 1-O-octadecyl-3-O-(N-acetyl)neuraminyl-sn-glycerol sodium salt was studied to see if sialic anomers were distinguishable by mass spectra. It was evident that, in the electrospray ionization and fast-atom bombardment product-ion spectra: (1) in the positive MS(2) product-ion spectrum, the beta- anomer showed an unexpected aglycone-side sodiated sodium alkoxide ion, which was absent for the a-anomer; (2) in both polarities the beta-anomer showed dehydration much more easily than the a-anomer; and (3) in the negative MS(2) product-ion spectrum, the P-anomer also readily showed decarboxylation. Our hypothesis is that, although several easily interconvertible conformations may be allowed, the one having the large aglycone in the equatorial orientation affects the collision-induced dissociation fragmentations. (J Am Soc Mass Spectrom 2009, 20, 394-397) (C) 2009 Published by Elsevier Inc. on behalf of American Society for Mass Spectrometry
Scientific journal, English

Spectroscopic Studies of the Light-Color Modulation Mechanism of Firefly (Beetle) Bioluminescence
Takashi Hirano; Yosuke Hasumi; Kazuhiro Ohtsuka; Shojiro Maki; Haruki Niwa; Minoru Yamaji; Daisuke Hashizume
Lead, Journal of the American Chemical Society, AMER CHEMICAL SOC, 131, 6, 2385-2396, Feb. 2009, Peer-reviwed, True, To reveal the light-color modulation mechanism of firefly (beetle) bioluminescence, we investigated the spectroscopic properties of the phenolate anion 1-O- generated from 5,5-dimethyloxyluciferin (1-OH) using various base/solvent combinations. Phenolate anion 1-O- is a model compound for the keto form of wild-type oxyluciferin phenolate anion (OL-), which is postulated to be the emitter of the bioluminescence. The fluorescence maxima of 1-O- were found to depend on the base/solvent combination used, and they varied in the range 541-640 nm, which covers the almost whole range of the bioluminescence emission maximum. In a polar solvent, where (1)(1-O-)* and the countercation (the conjugate acid of a base) make a solvent-separated ion pair or a free ion couple, the emission maxima of 1-O- were found to be modulated by the solvent polarity. In a less polar solvent, where (1)(1-O-)* and the countercation are formed as a contact ion pair, the strength of the covalent character of the O8'center dot center dot center dot H bond between (1)(1-O-)* and the countercation is operative. The effect of the base/solvent combination on the emission properties of (1)(1-O-)* was also verified using fluorescence lifetime measurements and density functional theory calculations on 1-O- and its ion-pair models. On the basis of these results, we propose the following light-color modulation mechanism: (1) the light emitter is the excited singlet state of OL- [ (1)(OL-)*], and (2) light emission from (1)(OL-)* is modulated by the polarity of the active-site environment of a luciferase and the degree of covalent character of the O8'center dot center dot center dot H bond between (1)(OL-)* and a protonated basic moiety in the active site. Mechanisms for variation of the bioluminescence colors and their applications are discussed.
Scientific journal, English

The reaction mechanism for the high quantum yield of Cypridina (Vargula) bioluminescence supported by the chemiluminescence of 6-aryl-2-methylimidazo[1,2-a]pyrazin-3(7H)-ones (Cypridina luciferin analogues)
Takashi Hirano; Yuto Takahashi; Hiroyuki Kondo; Shojiro Maki; Satoshi Kojima; Hiroshi Ikeda; Haruki Niwa
Lead, Photochemical & Photobiological Sciences, ROYAL SOC CHEMISTRY, 7, 2, 197-207, Feb. 2008, Peer-reviwed, Invited, True, To establish the reaction mechanism of the high-quantum-yield bioluminescence in Cypridina (Vargula), we investigated the chemiluminescence of 6-aryl-2-methylimidazo[1,2-a] pyrazin-3(7H)-ones (1H) as Cypridina luciferin analogues in DMSO-1,1,3,3-tetramethylguanidine and in diglyme-acetate buffer. We found that the chemiluminescence of 1H with an electron-donating aryl group, such as a 4-(dimethylamino) phenyl, 3-indolyl or 3-(1-methyl) indolyl group, gave a high quantum yield (Phi(CL)) in diglymeacetate buffer. This indicates that the reaction mechanism producing this high Phi(CL) involves the chemiexcitation of a neutral dioxetanone intermediate possessing an electron-donating aryl group to the singlet excited state of neutral acetamidopyrazine (the light emitter). In addition, we investigated the. fluorescence of acetamidopyrazines and performed DFT calculations for neutral dioxetanones and the transition states (TS) of the dioxetanone's decomposition. The results made it clear that the electron-donating aryl group gives the TS and the singlet-excited acetamidopyrazine (S-1) a strong intramolecular charge transfer (ICT) character, and their similar ICT character leads to the ICT TS -> S-1 route in the charge transfer-induced luminescence (CTIL) mechanism for efficient chemiexcitation. The reaction mechanism of the chemiluminescence of 1H can explain the highly efficient chemiexcitation of Cypridina bioluminescence.
Scientific journal, English

Spectroscopic and density functional theory studies of the molecular geometry and electronic structure of classical and nonclassical radical ions derived from 7-benzhydrylidenenorbornene analogues
Hayato Namai; Hiroshi Ikeda; Takashi Hirano; Hideki Ishii; Kazuhiko Mizuno
Journal of Physical Chemistry A, AMER CHEMICAL SOC, 111, 32, 7898-7905, Aug. 2007, Peer-reviwed, True, A spectroscopic study, using nanosecond time-resolved laser flash photolysis and gamma-irradiation of low-temperature matrices, was undertaken along with a theoretical study using density functional theory (DFT) and time-dependent (TD)-DFT calculations to gain insight into the molecular geometry and electronic structure of radical cations and radical anions of 7-benzhydrylidenenorbornene (4) and its derivatives 6-8. The radical ions 4(.+), 6(.+), 7(.+), 8(.+), 4(.-), 6(.-), 7(.-), and 8(.-) exhibited clear absorption bands in the 350-800 nm region, which were reproduced successfully from the electronic transitions calculated with TD-UB3LYP/cc-pVDZ. Radical cations 4(.+) and 8(.+) are consistent with a bent structure having a delocalized electronic state where the spin and charge are delocalized not only in the benzhydrylidene subunit but also in the residual subunit. In contrast, 6(.+) and 7(.+) have nonbent structures with a localized electronic state where their spin and charge are localized in the benzhydrylidene subunit only. Therefore, 4(.+) and 8(.+) have a nonclassical nature, with 6(.+) and 7(.+) possessing a classical nature. In contrast, in the radical anion system, 7(.-) and 8(.-) are considered nonclassical, and 4(.-) and 6(.-) are classical. Orbital interaction theory and DFT calculations can account fully for the spectroscopic features, molecular geometries, and electronic structures of the radical ions. For example, the shift of the absorption bands and the nonclassical nature of 4(.+) are due to the antibonding character of the highest occupied molecular orbital (HOMO) of 4, and those of 7(.-) arise from the bonding character of the lowest unoccupied molecular orbital (LUMO) of 7. A topological agreement of p-orbitals at C-2, C-3 (or C-5, C-6), and C-7 produces strong electronic coupling with an antibonding or a bonding character in the frontier orbitals. It is the ethylene and butadiene skeleton at C-2-C-3 (or C-5-C-6), with its contrasting topology in the HOMO and LUMO of the neutral precursor, that holds the key to deducing the nonclassical nature of the 7-benzhydrylidenenorbornene-type radical cation and radical anion systems.
Scientific journal, English

Chemiluminescence of 6-aryl-2-methylimidazo[1,2-a]pyrazin-3(7H)-ones in DMSO/TMG and in diglyme/acetate buffer: support for the chemiexcitation process to generate the singlet-excited state of neutral oxyluciferin in a high quantum yield in the Cypridina (Vargula) bioluminescence mechanism
Yuto Takahashi; Hiroyuki Kondo; Shojiro Maki; Haruki Niwa; Hiroshi Ikeda; Takashi Hirano
Corresponding, Tetrahedron Letters, PERGAMON-ELSEVIER SCIENCE LTD, 47, 34, 6057-6061, Aug. 2006, Peer-reviwed, True, The chemiluminescence of 6-aryl-2-methylimidazo [1,2-a]pyrazin-3 (7 H) -ones (Cypridina luciferin analogues) in DMSO/ 1,1,3,3-tetramethylguanidine and in diglyme/acetate buffer was investigated. The results indicate that the reaction mechanism that produces a high chemiluminescence quantum yield involves a chemiexcitation process from a neutral dioxetanone intermediate possessing an electron-donating aryl group (sigma(Ar) <-0.6) to the singlet-excited state of neutral acetamidopyrazine. This result may be applied to the reaction mechanism for Cypridina (Vargula) bioluminescence. (c) 2006 Elsevier Ltd. All rights reserved.
Scientific journal, English

Real light emitter in the bioluminescence of the calcium-activated photoproteins aequorin and obelin: light emission from the singlet-excited state of coelenteramide phenolate anion in a contact ion pair
Kotaro Mori; Shojiro Maki; Haruki Niwa; Hiroshi Ikeda; Takashi Hirano
Corresponding, Tetrahedron, PERGAMON-ELSEVIER SCIENCE LTD, 62, 26, 6272-6288, Jun. 2006, Peer-reviwed, True, Fluorescence of the phenolate anion (3(O)(-)) and the amide anion (5(N)(-)) of coelenteramide analogues in ion pairs with various counter cations was systematically investigated to elucidate the ionic structure of the light emitter in the bioluminescence of the calcium-activated photoproteins aequorin and obelin. The fluorescent properties of 3(O)- in an ion pair with a conjugate acid of an organic base (BASE-H+) were varied depending on the structural variation of the ion pair and the solvent polarity. In particular, the fluorescence of 3(O)- in the ion pair with the conjugate acid of n-butylamine (NBA-H+) indicates that the singlet-excited state of 3(O)(-) ((1)3(O)(-)*) and NBA-H+ make a contact ion pair in which the fluorescence emission maxima of 3(O)- is sensitive to the solvent polarity and the fluorescence quantum yields of 3(O)- increase in a less polar solvent. The results also confirm that (1)3(O)-* is a twisted intramolecular charge transfer state. By contrast, the fluorescence of 5(N)(-) in an ion pair depends little on the BASE-H+ or the solvent polarity. Based on these results, we conclude that the light emitter in aequorin and obelin bioluminescences is the singlet-excited state of coelenteramide phenolate anion 2(O)(-)((1)2(O)(-)*) in a contact ion pair with an imidazolium side chain of a histidine residue, which is located at the less polar active sites of the photoproteins. We also propose a mechanism for the bioluminescence reaction, including the chemiexcitation process to give (1)2(O)(-)*. (c) 2006 Elsevier Ltd. All rights reserved.
Scientific journal, English

Bio-inspired materials for electron donors and charge-transfer complex formation based on the imidazopyrazinone luciferin core
M Suzuki; T Fujii; T Nogami; T Hirano; T Ishida
Chemistry Letters, CHEMICAL SOC JAPAN, 35, 3, 250-251, Mar. 2006, Peer-reviwed, True, The electron-donating properties of 2-phenyl- and 2-methylimidazo[1,2-a]pyrazin-3(7H)-ones were confirmed by the oxidation potentials. The I/I molecular complex from the former and TCNQ was characterized by means of X-ray crystallographic analysis, and the charge-transfer degree was estimated to be 16% from the IR nitrile stretching bands.
Scientific journal, English

Construction of a new firefly bioluminescence system using L-luciferin as substrate
M Nakamura; K Niwa; S Maki; T Hirano; Y Ohmiya; H Niwa
Tetrahedron Letters, PERGAMON-ELSEVIER SCIENCE LTD, 47, 7, 1197-1200, Feb. 2006, Peer-reviwed, True, L-Luciferin can be converted into D-luciferin with an enzyme/co-factor system consisting of firefly luciferase, an esterase, ATP, Mg2+, and coenzyme A. By this means, a new firefly bioluminescence system can be constructed that uses L-luciferin as the substrate. (c) 2005 Published by Elsevier Ltd.
Scientific journal, English

Substituent effects on the kinetics for the chemiluminescence reaction of 6-arylimidazo[1,2-a]pyrazin-3(7H)-ones (Cypridina luciferin analogues): support for the single electron transfer (SET)-oxygenation mechanism with triplet molecular oxygen
H Kondo; T Igarashi; S Maki; H Niwa; H Ikeda; T Hirano
Tetrahedron Letters, PERGAMON-ELSEVIER SCIENCE LTD, 46, 45, 7701-7704, Nov. 2005, Peer-reviwed, True, Kinetics of chemiluminescence reactions of 2-methyl-6-phenylimidazo[1,2-a]pyrazin-3 (7H)-one (1c, Cypridina luciferin analogue) and substituent effects of the 6-aryl group of derivatives 1 strongly suggest that the rate-determining step is a single electron transfer from an anion derived from 1 to a triplet molecular oxygen (O-2) in the oxygenation process. (c) 2005 Elsevier Ltd. All rights reserved.
Scientific journal, English

Substituent effects on the spectroscopic properties of solvatochromic 2-phenylimidazo[1,2-a]pyrazin-3(7H)-ones: an effective control for the colorimetric sensor properties
Y Takamuki; S Maki; H Niwa; H Ikeda; T Hirano
Corresponding, Tetrahedron, PERGAMON-ELSEVIER SCIENCE LTD, 61, 42, 10073-10080, Oct. 2005, Peer-reviwed, True, Substituent effects on the spectroscopic properties of a solvatochromic compound, 7-methyl-2-phenylimidazo[1,2-a]pyrazin-3(7H)-one (1c), using derivatives 1 with a para-substituent R on the phenyl group, were investigated systematically. In the UV/visible absorption spectra, the solvatochromic property of I originating from hydrogen-bonding interactions was effectively regulated by the substituent effects. In particular, the cyano derivative le showed significant solvatochromism with a wide color variation range and a high sensitivity toward solvents. Similarly, the fluorescence of I showed a redshift as the electron-withdrawing property of R increased. The substituent effects were evaluated by AM1-COSMO calculations, which also suggested that derivatives 1 are good electron donors and that the electron-donating ability is regulated by R. This was confirmed by the observation of low oxidation potentials and the formation of charge-transfer complexes with tetracyanoethylene. Absorption-spectrum changes of le and le caused by metal-ion complexation were also compared, showing that the cyano derivative le is a good colorimetric sensor for the Lewis acidity of the metal ions. From these observations, it was established that para-substitution of R on the phenyl group of le caused successive modulations of the colorimetric sensor properties. (c) 2005 Elsevier Ltd. All rights reserved.
Scientific journal, English

Spectroscopic and DFT studies of nonclassical and classical radical cations of 7-benzhydrylidenenorbornene analogues: contrasting molecular geometry and electronic structures originating from the different patterns of electronic coupling
H Ikeda; H Namai; T Hirano
Tetrahedron Letters, PERGAMON-ELSEVIER SCIENCE LTD, 46, 44, 7631-7635, Oct. 2005, Peer-reviwed, True, Nanosecond time-resolved UV/vis absorption spectroscopy on laser flash photolysis and calculations based on (time-dependent) density functional theory for radical cations of 7-benzhydrylidenebenzonorbornene (3) and 7-benzhydrylidene-2,3-dimethylenenorbornane (4) indicated their contrasting molecular geometry and electronic structures, suggesting the nonclassical and classical nature of 3(center dot+) and 4(center dot+), respectively, which originated from the different patterns of electronic coupling between the C-7-C-8 and C-2-C-3 subunits. (c) 2005 Elsevier Ltd. All rights reserved.
Scientific journal, English

Firefly luciferase exhibits bimodal action depending on the luciferin chirality
M Nakamura; S Maki; Y Amano; Y Ohkita; K Niwa; T Hirano; Y Ohmiya; H Niwa
Biochemical and Biophysical Research Communications, ACADEMIC PRESS INC ELSEVIER SCIENCE, 331, 2, 471-475, Jun. 2005, Peer-reviwed, True, Firefly luciferase is able to convert (L)-luciferin into luciferyl-CoA even under ordinary aerobic luciferin-luciferase reaction conditions. The luciferase is able to recognize strictly the chirality of the luciferin structure, serving as the acyl-CoA synthetase for (L)-luciferin, whereas (D)-luciferin is used for the bioluminescence reaction. (D)-Luciferin inhibits the luciferyl-CoA synthetase activity Of (L)-luciferin, whereas (L)-luciferin retards the bioluminescence reaction Of (D)-luciferin, meaning that both enzyme activities are prevented by the enantiomer of its own substrate. © 2005 Elsevier Inc. All rights reserved.
Scientific journal, English

Spectroscopic and DFT evidence for a nonclassical radical cation derived from 7-benzhydrylidenenorbornene
H Ikeda; H Namai; T Hirano
Tetrahedron Letters, PERGAMON-ELSEVIER SCIENCE LTD, 46, 22, 3917-3921, May 2005, Peer-reviwed, True, Nanosecond time-resolved UV/vis absorption spectroscopy on laser flash photolysis was conducted for photoinduced electron-transfer reactions of 7-benzhydrylidenenorbornene (1) and 7-benzhydrylidenenorbornane (5). The differences in the observed absorption bands and the structures of 1(&BULL;+) and 5(&BULL;+) were evaluated successfully using calculations based on (time dependent) density functional theory, confirming the nonclassical nature of 1(&BULL;+). © 2005 Elsevier Ltd. All rights reserved.
Scientific journal, English

Bioluminescence activity of Latia luciferin analogues: replacement of the 2,6,6-trimethylcyclohexene ring onto the methyl-substituted phenyl groups
M Nakamura; M Mamino; M Masaki; S Maki; R Matsui; S Kojima; T Hirano; Y Ohmiya; H Niwa
Tetrahedron Letters, PERGAMON-ELSEVIER SCIENCE LTD, 46, 1, 53-56, Jan. 2005, Peer-reviwed, True, A series of Latia luciferin analogues having methyl-substituted phenyl groups instead of the natural 2.6.6-trimethylhexene ring was synthesized and their bioluminescence activity were measured. The Latia luciferase was found to be able to moderately recognize the appropriately methyl-substituted phenyl analogues with the same light production kinetics as. that of natural luciferin. (C) 2004 Elsevier Ltd. All rights reserved.
Scientific journal, English

Characterization of [1-13C]- Specifically Labeled Amino Acids Using ESIMS/MS in the Selected Reaction Monitoring Mode
Ohashi, Y; Hatase, H; Nakamura, M; Hirano, T; Maki, S; Niwa, H
J. Mass Spectrom. Soc. Jpn., Mass Spectrometry Society of Japan, 53, 6, 309-314, 2005, Peer-reviwed, True, ESIMS/MS was employed for the analyses of 1-¹³CO-labeled amino acids. Conventionally, in order to estimate the ¹³C-content, the intensity of molecule-related ion of the sample has been compared against the natural compound. However, this method is incompetent for specifying the position of the ¹³C-labeling, hence is unable to distinguish the specifically 1-¹³C-labeled compound from otherwise-(generally or non-specifically) labeled amino acids. With the intention of distinguishing 1-¹³CO-labeled amino acids from generally labeled and non-labeled molecules we utilized ESIMS/MS in the selected reaction monitoring mode, choosing the protonated molecules as the precursor ion and specifying the product ion generated by a 47 u- (instead of 46 u-) elimination from the precursor ion for the labeled samples. By this new method, characterization of solely 1-¹³CO-labeled amino acids has been successfully conducted, enabling their distinction from otherwise-labeled compounds.
Scientific journal, English

Regioselective phenyl-substitution effects on the solvatochromism of 2-phenylimidazo[1,2-a]pyrazin-3(7H)-one derivatives: expansion of the color variation range of a visible indicator for the proton donor ability of solvents
S Fujio; D Hashizume; Y Takamuki; M Yasui; F Iwasaki; S Maki; H Niwa; H Ikeda; T Hirano
Corresponding, Tetrahedron Letters, PERGAMON-ELSEVIER SCIENCE LTD, 45, 46, 8531-8534, Nov. 2004, Peer-reviwed, True, Phenyl-substitution to the C8 position of an imidazopyrazinone ring resulted in the significant bathochromic shift of the lowest energy band, while the substitution to the C6 position does not produce such a shift. This provides evidence that a color variation range of the solvatochromism of 2-phenylimidazopyrazinone derivatives depends strongly on the position of phenyl-substitution. Results indicated that an imidazopyrazinone with the phenyl groups at the C2 and C8 positions acts as a potential indicator of the proton donor ability of solvents. (C) 2004 Elsevier Ltd. All rights reserved.
Scientific journal, English

Substituent effects on the solvatochromism of 2-phenylimidazopyrazinones: Effective control of the color variation range and sensitivity toward an indication of the proton-donor ability of solvents by an electron-withdrawing group substitution
Y Takamuki; S Maki; H Niwa; H Ikeda; T Hirano
Corresponding, Chemistry Letters, CHEMICAL SOC JAPAN, 33, 11, 1484-1485, Nov. 2004, Peer-reviwed, True, A para-substitution on the phenyl group of 2-phenylimida-zopyrazinone successively resulted in a change of the solvato-chromic property, especially of the color-variation range and sensitivity to solvents, demonstrating that derivatives possessing an electron-withdrawing group are preferable as potential indicators of the proton-donor ability of solvents.
Scientific journal, English

Synthesis and chemiluminescence of novel p-conjugated bisimidazopyrazinone derivatives
Mika Niibe; Susumu Obata; Shojiro Maki; Haruki Niwa; Takashi Hirano
Corresponding, Luminescence, 19, 3, 166-166, Aug. 2004, True
International conference proceedings, English

Spectral control of 2-arylimidazopyrazinone derivatives: substituent and an interaction with biological molecules
Yoshiharu Takamuki; Shojiro Maki; Haruki Niwa; Takashi Hirano
Corresponding, Luminescence, 19, 3, 177-177, Aug. 2004, True
International conference proceedings, English

The chemiluminescence reaction mechanism of imidazopyrazinones: Effects of the reaction conditions for the chemiluminescence
Hiroyuki Kondo; Shojiro Maki; Haruki Niwa; Takashi Hirano
Corresponding, Luminescence, 19, 3, 155-155, Aug. 2004, True
International conference proceedings, English

Development of the chemistry of the imidazopyrazinone- bioluminescence system: From the bio- and chemiluminescence mechanism to a design of sensor molecules
Takashi Hirano; Shuichiro Nakai; Takasi Sekiguchi; Shunsuke Fujio; Shojiro Maki; Haruki Niwa
Lead, Luminescence, 19, 3, 14-14, Aug. 2004, True
International conference proceedings, English

Ionic structure of the excited light – emitter in the calcium – activated photoprotein bioluminescence”
Kotaro Mori; Shojiro Maki; Haruki Niwa; Takashi Hirano
Corresponding, Luminescence, 19, 3, 14-14, Aug. 2004, True
International conference proceedings, English

Synthesis and bioluminescent activity of the Latia luciferin analogs
Yoshiharu Amano; Mitsuhiro Nakamura; Shojiro Maki; Takashi Hirano; Yoshihiro Ohmiya; Haruki Niwa
Luminescence, 19, 3, 24-24, Aug. 2004, True
International conference proceedings, English

Synthesis of Latia luciferin benzoate analogues and their bioluminescent activity
M Nakamura; M Masaki; S Maki; R Matsui; M Hieda; M Mamino; T Hirano; Y Ohmiya; H Niwa
Tetrahedron Letters, PERGAMON-ELSEVIER SCIENCE LTD, 45, 10, 2203-2205, Mar. 2004, Peer-reviwed, True, The bioluminescent system of the univalve shell Latia neritoides exhibits a luciferin-luciferase reaction. We study the enol formate structure of Latia luciferin, which is expected to be important for luminescent activity. The Latia luciferin analogues with an enol substituted benzoate moiety were synthesized and their bioluminescent activity was measured. The Latia luciferin benzoate analogues delay emission for natural luciferin in bioluminescence, indicating that the Latia bioluminesent activity can be controlled by the design of the enol ester. (C) 2004 Elsevier Ltd. All rights reserved.
Scientific journal, English

Metal-ion complexation of imidazo[1,2-a]pyrazin-3(7H)-ones: continuous changes in absorption spectra of complexes depending on the Lewis acidity of the metal ion
T Sekiguchi; S Maki; H Niwa; H Ikeda; T Hirano
Corresponding, Tetrahedron Letters, PERGAMON-ELSEVIER SCIENCE LTD, 45, 5, 1065-1069, Jan. 2004, Peer-reviwed, True, The spectroscopic properties of metal-ion complexes of several imidazopyrazinone derivatives with Li+, Mg2+, Ca2+, Ba2+, Sc3+, and La3+ ions were studied. The spectral characteristics and the formation constants of the complexes changed continuously depending on the Lewis acidity of the metal ion, suggesting that the imidazopyrazinones can find application as indicators of Lewis acidity. In the case of bis-imidazopyrazinone derivatives, the complexation abilities were enhanced by chelate effects. (C) 2003 Elsevier Ltd. All rights reserved.
Scientific journal, English

Analysis of sugar epimers using mass spectrometry: N-acetyllactosamine-6,6 '-disulfate and the 2 '-epimer
Y Ohashi; Y Itoh; M Kubota; K Hamada; M Ohashi; T Hirano; H Niwa
European Journal of Mass Spectrometry, IM PUBLICATIONS, 10, 2, 269-278, 2004, Peer-reviwed, True, Galbeta1-4GlcNAc-6,6'-disulfate and 2'-epimer corresponding to Galbeta1-4ManNAc-6,6'-disulfate were distinguished by mass spectrometry by utilizing fast atom bombardment (FAB), electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) methods. As for the steric information, negative-ion ESI mass spectrometry/mass spectrometry (MS/MS) provides the most extensive data, but FAB MS/MS also reveals detailed structural information of interest in our case, where MALDI MS is not yet fully equipped with post-source decay.
Scientific journal, English

Fundamental studies on the structures and spectroscopic properties of imidazo[1,2-a]pyrazin-3(7H)-one derivatives
S Nakai; M Yasui; M Nakazato; F Iwasaki; S Maki; H Niwa; M Ohashi; T Hirano
Bulletin of the Chemical Society of Japan, CHEMICAL SOC JAPAN, 76, 12, 2361-2387, Dec. 2003, Peer-reviwed, True, The fundamental physical properties of 2-methyl and 2-phenylimidazo[1,2-a]pyrazin-3(7H)-one 1 and 2, and their N- and O-alkylated derivatives 3-6 have been investigated by X-ray crystallography, UV/vis absorption spectroscopy, NMR, and AMl-COSMO calculations. The crystal structures of 3 and 4 showed that the imidazo[1,2-a]pyrazin-3(7H)-one (imidazopyrazinone) pi-system has a planar ring structure and a weakened carbonyl character of the C3-O10 bond, suggesting that the imidazopyrazinone pi-system has the character of a zwitter-ionic resonance structure to increase the aromaticity. The data concerning the bond length alternations and the NMR chemical shifts of 1-4 also support that their imidazopyrazinone rings have small portions of aromatic character. In addition, imidazopyrazinone derivatives 1-4 showed solvatochromism originating by hydrogen-bonding interactions with hydrogen-bond donor solvent molecules; derivatives 1 and 2 prefer to be the NH form isomers in their tautomeric equilibriums. These observations were consistently evaluated by MO calculations. The physical properties of protonated species of 1-6 and anion species of 1 and 2 were also established. The fundamental properties of the imidazopyrazinone pi-system explain the several problems of the chemi- and bioluminescence reactivities of imidazopyrazi none derivatives and of the construction of a bioluminescent supramolecule.
Scientific journal, English

Pd black deposited on polypropylene sheet as a highly selective catalyst for hydrogenation of alkenes
S Maki; M Okawa; T Makii; T Hirano; H Niwa
Tetrahedron Letters, PERGAMON-ELSEVIER SCIENCE LTD, 44, 18, 3717-3721, Apr. 2003, Peer-reviwed, True, A catalyst deposited on a polypropylene sheet having an activity of almost the same level as commercially available Pd black and capable of promoting hydrogenolysis-free hydrogenation was developed. (C) 2003 Elsevier Science Ltd. All rights reserved.
Scientific journal, English

Hydrogenolysis-free Hydrogenation Using Pd Black Catalyst Deposited on Pd Sheet
Maki, S; Okawa, M; Makii, T; Hirano, T; Niwa, H
ITE Letters, 4, 49-54, 2003, Peer-reviwed, True
Scientific journal, English

Viscosity-dependent fluorescence decay of the GFP chromophore in solution due to fast internal conversion
AD Kummer; C Kompa; H Niwa; T Hirano; S Kojima; ME Michel-Beyerle
Journal of Physical Chemistry B, AMER CHEMICAL SOC, 106, 30, 7554-7559, Aug. 2002, Peer-reviwed, True, Time-resolved fluorescence measurements at 275 K show that the excited-state lifetime of a model chromophore of the green fluorescent protein (GFP) substantially increases from subpicoseconds in low-viscosity solvents such as ethanol (eta = 1.7 cP) to 30 ps in glycerol (eta = 9.9 x 10(3) cP) and reaches 2.1 ns in glycerol glass at 150 K. At high temperatures the similarity of excited-state decay and ground-state recovery kinetics indicates internal conversion being responsible for the short fluorescence lifetimes. Their viscosity dependence reflects on a motion with a considerable amplitude that is damped by viscous drag and outweighs thermal activation as is concluded from measurements at different temperatures. In solution the neutral and the anionic forms of the model chromophore are similarly nonfluorescent in contrast to wild-type GFP and mutants where the deprotonated form is hardly undergoing internal conversion. Thus, the protein selectively restricts motional degrees of freedom of the chromophore in specific protonation states.
Scientific journal, English

Preparation of deoxygenated derivatives of neoanisatin, a neurotoxic sesquiterpenoid having a beta-lactone
K Obitsu; S Maki; T Hirano; H Niwa
Bulletin of the Chemical Society of Japan, CHEMICAL SOC JAPAN, 75, 2, 347-354, Feb. 2002, Peer-reviwed, True, Seven deoxygenated neoanisatin derivatives were prepared from anisatin and neoanisatin by utilizing methoxalyl ester/tributylstannane (n-Bu3SnH) deoxygenation procedure coupled with a novel dehydration reaction of neoanisatin.
Scientific journal, English

Preparation and Toxic Property of Carbapicrotoxinin, a Cyclopropane-containing Analog of GABA-antagonistic Sesquiterpenoid Piricrotoxinin
Kazuyoshi Obitsu; Shojiro Maki; Takashi Hirano; Haruki Niwa
ITE Letters, ITE Letters, 3, 72-75, 2002, Peer-reviwed, True
Scientific journal, English

Reduction in Desorption Mass Spectrometry: Multiple Protonation on Flavins without Charge Increment
Itoh, Y; Ohashi, Y; Shibue, T; Hayashi, A; Maki, S; Hirano, T; Niwa, H
J. Mass Spectrom. Soc. Jpn., Mass Spectrometry Society of Japan, 50, 2, 52-57, 2002, Peer-reviwed, True, Three flavin-containing compounds, namely, riboflavin, riboflavin 5′-phosphate (flavin mononucleotide, FMN) and flavin-adenine dinucleotide (FAD, Scheme 1), were studied using matrix-assisted laser desorption ionization (MALDI), fast atom bombardment (FAB) and electrospray ionization (ESI) mass spectrometry. It was found that the isoalloxazine ring (flavin) was reduced in the positive-ion MALDI and FAB ionization processes producing unusual ions [M+2]^+· and [M+3]⁺ in addition to the anticipated [M+1]⁺, whereas ESI generated only [M+H]⁺ as the molecular-related ion. The reduction mechanism is hypothesized as the protonation from the matrix with a concomitant electron transfer,^*1 rather than the transfer of hydrogen atom(s), H^·_·ESI, in which matrix is not used, did not produce [M+2]^+· nor [M+3]⁺ more than the natural isotope abundance of ¹³C in the sample molecules. The reduction site expands to N(1)=C(10a)-C(4a)=N(5), a1,4-diaza-1,3-butadiene system, in the isoalloxazine ring, resembling the behavior of prosthetic groups of aerobic dehydrogenases.
Scientific journal, English

Fluorescence properties of phenolate anions of coelenteramide analogues: the light-emitter structure in aequorin bioluminescence
Y Imai; T Shibata; S Maki; H Niwa; M Ohashi; T Hirano
Corresponding, Journal of Photochemistry and Photobiology A-Chemistry, ELSEVIER SCIENCE SA, 146, 1-2, 95-107, Dec. 2001, Peer-reviwed, True, To elucidate the ionic structure of the excited state of light-emitter coelenteramide in aequorin bioluminescence, the fluorescent properties of phenolate anions of coelenteramide analogues were investigated. Fluorescence of phenolate anion in non-polar solvents was observed by electronic excitation of a 1: 1 hydrogen-bonded complex of a coelenteramide analogue with a hydrogen-bond donor molecule such as n-butylamine. In polar solvents, the phenolate anion was directly generated using a base, and its fluorescence was studied. These results confirm that the singlet-excited state of phenolate anion of coelenteramide has an intramolecular CT character, and that its fluorescence emission wavelength changes depending upon solvent polarity. The fluoro-substituent effect on the fluorescent property of phenolate anions was also clarified to help in explaining the bioluminescent property of fluorinated semi-synthetic aequorin. These results consistently support the assignment that the phenolate anion is the ionic structure of the excited light-emitter in BFP during AQ bioluminescence. (C) 2001 Elsevier Science B.V. All rights reserved.
Scientific journal, English

Effect of solvent and hydrogen during selective hydrogenation
S Maki; Y Harada; R Matsui; M Okawa; T Hirano; H Niwa; M Koizumi; Y Nishiki; T Furuta; H Inoue; C Iwakura
Tetrahedron Letters, PERGAMON-ELSEVIER SCIENCE LTD, 42, 47, 8323-8327, Nov. 2001, Peer-reviwed, True, Described is the solvent effect for the chemoselective hydrogenation of alkenes having a benzyloxy group (Bn-O-) using a hydrogenation system employing atomic hydrogen permeating through a Pd sheet electrode. (C) 2001 Elsevier Science Ltd. All rights reserved.
Scientific journal, English

Hydrogenolysis-free hydrogenation by Pd black powder catalyst
S Maki; M Okawa; R Matsui; T Hirano; H Niwa
Synlett, GEORG THIEME VERLAG KG, 10, 1590-1592, Oct. 2001, Peer-reviwed, True, A new general method of hydrogenolysis-free hydrogenation using a commercially available Pd black powder catalyst has developed.
Scientific journal, English

Improved Syntheses of Watasenia Preluciferin (Coelenterazine) and Watasenia Luciferin (Coelenterazine Disulfate), and Site Specific Syntheses of the Coelenterazine Monosulfates
Kojima, S; Maki, S; Hirano, T; Ohashi, M; Tsuji, F. I; Niwa, H
ITE Letters, 3, 393-397, 2001, Peer-reviwed, True
Scientific journal, English

Facile Cleavage Reactions of Styrylic Olefins using Electrochemical Methods
Shojiro Maki; Haruki Niwa; Takashi Hirano
Synlett, Georg Thieme Verlag KG, 12, 12, 1385-1386, 31 Dec. 2000, Peer-reviwed, Negative constant current electrolysis of styrylic olefins in an aqueous solvent resulted in the oxidative cleavage of the double bonds, giving carbonyl compounds in good yields. The double bond conjugated with more than one aromatic ring was selectively cleaved.
Scientific journal, English

Novel Dehydration Reaction of Neoanisatin and Transformation of Neoanisatin into Anisatin
Junko Yoshizawa; Kazuyoshi Obitsu; Shojiro Maki; Haruki Niwa; Takashi Hirano; Mamoru Ohashi
Synlett, Georg Thieme Verlag KG, 12, 12, 1387-1388, 31 Dec. 2000, Peer-reviwed, Reaction of neoanisatin with methyl oxalyl chloride in pyridine gave a novel dehydration product, from which anisatin was prepared.
Scientific journal, English

Isoquinoline formation by a novel photochemical intermolecular cycloaddition of 1,1-diphenylethene derivatives to 1,4-dicyanobenzene
H Ishii; Y Imai; T Hirano; S Maki; H Niwa; M Ohashi
Tetrahedron Letters, PERGAMON-ELSEVIER SCIENCE LTD, 41, 33, 6467-6471, Aug. 2000, Peer-reviwed, True, Phenanthrene-sensitized photoreaction of 1,1-diphenylethene (DPE) derivatives and 1,4-dicyanobenzene (DCNB) in benzene leads to a novel intermolecular cycloaddition to give isoquinoline derivatives as a novel synthetic method. The feasibility of this reaction was dependent upon the side chain structure of DPE derivatives, which would regulate the stability of radical cation DPE+. in a highly polar exciplex, and/or a contact radical ion pair, by hyperconjugation or neighboring group participation. (C) 2000 Elsevier Science Ltd. All rights reserved.
Scientific journal, English

Bioluminescence activity of Latia luciferin analogs
S Kojima; S Maki; T Hirano; Y Ohmiya; H Niwa
Tetrahedron Letters, PERGAMON-ELSEVIER SCIENCE LTD, 41, 22, 4409-4413, Jun. 2000, Peer-reviwed, True, Latia luciferin analogs were synthesized and their bioluminescence activities were measured. The Latia luciferase was found to recognize strictly the 2,6,6-trimethylcyclohexene ring moiety in the luciferin structure. While the enol ether analogs exhibited no bioluminescence activity, the corresponding enol acetate analog possessed 60% activity compared to natural luciferin having an enol formate structure, implying that the initial step of the light producing reaction is an enzymatic hydrolysis to yield the corresponding enolate anion. (C) 2000 Elsevier Science Ltd. All rights reserved.
Scientific journal, English

Supramolecular steric effects as the means of making reactive carbon radicals persistent. Quantitative characterization of the external surface of MFI zeolites through a persistent radical probe and a langmuir adsorption isotherm
T Hirano; W Li; L Abrams; PJ Krusic; MF Ottaviani; NJ Turro
Journal of Organic Chemistry, AMER CHEMICAL SOC, 65, 5, 1319-1330, Mar. 2000, Peer-reviwed, True, The photochemistry of tetraphenylacetone (1) adsorbed on the external surface of a MFI zeolite (the sodium form of LZ-105) has been investigated in combination with computational chemistry, surface area measurements, EPR analysis, and classical adsorption isotherms. All of the methods are consistent with a supramolecular structural model in which 1 is first adsorbed strongly through intercalation of a single benzene ring into a hole on the LZ-105 external surface (site I) followed by a weaker binding to the external framework between the holes (site II) until a monolayer of 1 is formed. From both computational and surface area measurements, it is estimated that the site I holes. on the external surface will be filled at ca. 0.3-0.5 wt %/wt loading of 1/LZ-105, which corresponds to 6.5 x 10(18) (ca. 10(-5) mel) of holes or molecules of 1 adsorbed in holes per gram of zeolite. The supramolecular composition of ca. 0.3-0.5% of 1 on LZ-105 characterizes a "break point" for the photochemistry and the EPR measurements, since it represents the value for saturation of the site I holes with 1. These conclusions are supported quantitatively by experimental isotherms of the adsorption of 1 on LZ-105. Photolysis of 1 intercalated in the site I holes causes fragmentation into two isomeric supramolecular diphenylmethyl (DPM) radicals, one (DMP)(in) which is adsorbed into the internal surface and becomes strongly persistent (half-life of many weeks) and the other (DMP)(ex) which diffuses on-the external surface and rapidly dimerizes (less than a few minutes) to produce the radical-radical combination product tetraphenylethane (2). Photolysis of 1 adsorbed on the solid external surface produces two supramolecularly equivalent DPM radicals (DMP)(ex) that diffuse on the external surface and rapidly dimerize to produce 2, and do not produce persistent DPM radicals.
Scientific journal, English

Synthesis, chemi- and bioluminescence properties, and photolysis of a coelenterazine analogue having a photoreactive azido group
JL Zheng; FQ Chen; T Hirano; Y Ohmiya; S Maki; H Niwa; M Ohashi
Bulletin of the Chemical Society of Japan, CHEMICAL SOC JAPAN, 73, 2, 465-469, Feb. 2000, Peer-reviwed, True, A photoreactive analogue of coelenterazine having an azido group was synthesized. The analogue showed similar chemi- and bioluminescence properties to those of the natural coelenterazine. Photolysis of the analogue in the presence of diethylamine gave a derivative azepine as the major product.
Scientific journal, English

Selective alkene hydrogenation with atomic hydrogen permeating through a Pd sheet electrode
S Maki; Y Harada; T Hirano; H Niwa; Y Yoshida; S Ogata; S Nakamatsu; H Inoue; C Iwakura
Synthetic Communications, TAYLOR & FRANCIS INC, 30, 19, 3575-3583, 2000, True, Chemoselective hydrogenation of olefinic double bonds without concomitant hydrogenolysis of allylic and benzylic C-O linkages was performed successfully by the aid of active hydrogen permeated through a Pd sheet electrode.
Scientific journal, English

A Spectroscopic Study of Diphenylmethyl Radicals and Diphenylmethyl Carbocations Stabilized by Zeolites (共著)
Jockusch, S; Hirano, T; Liu, Z; Turro, N. J
J. Phys. Chem. B, American Chemical Society, 104, 6, 1212-1216, 2000, Peer-reviwed, True
Scientific journal, English

Reversible oxygenation of a diphenylmethyl radical rendered supramolecularly persistent
T Hirano; W Li; L Abrams; PJ Krusic; MF Ottaviani; NJ Turro
Journal of the American Chemical Society, AMER CHEMICAL SOC, 121, 30, 7170-7171, Aug. 1999, Peer-reviwed, True
Scientific journal, English

Reactivity and pi-facial selectivity of nucleophile addition to the radical cations of 7-benzhydrylidenenorbornene derivatives
H Ishii; S Shiina; T Hirano; H Niwa; M Ohashi
TETRAHEDRON LETTERS, PERGAMON-ELSEVIER SCIENCE LTD, 40, 3, 523-526, Jan. 1999, For correlating a homoconjugation structure of a radical cation to its reactivity with a nucleophile, the reactivity and pi-facial selectivity of CH3OH and H2O addition to the radical cations of 7-benzhydrylidenenorbornene derivatives generated by photoinduced electron transfer reactions were investigated. (C) 1998 Elsevier Science Ltd. All rights reserved.
Scientific journal, English

Stereoselective tandem cyclization of 1,1-diphenyl-1,n-alkadienes via photoinduced electron transfer reaction
H Ishii; R Yamaoka; Y Imai; T Hirano; S Maki; H Niwa; D Hashizume; F Iwasaki; M Ohashi
Tetrahedron Letters, PERGAMON-ELSEVIER SCIENCE LTD, 39, 51, 9501-9504, Dec. 1998, Peer-reviwed, True, The photoinduced electron transfer reaction of 1,1-diphenyl- 1,n-alkadienes in the presence of phenanthrene and 1,4-dicyanobenzene as a sensitizer and an electron acceptor, respectively gave intramolecular tandem cyclization products in highly stereocontrolled manner. (C) 1998 Elsevier Science Ltd. All rights reserved.
Scientific journal, English

Bioluminescent properties of fluorinated semi-synthetic aequorins
T Hirano; Y Ohmiya; S Maki; H Niwa; M Ohashi
Lead, Tetrahedron Letters, PERGAMON-ELSEVIER SCIENCE LTD, 39, 31, 5541-5544, Jul. 1998, Peer-reviwed, True, Bioluminescent properties of semi-synthetic aequorins containing coelenterazine analogues possessing fluoro group(s) on the 6-(4-hydroxyphenyl) group match the fluorescent behavior of the phenolate anions of the corresponding fluorinated coelenteramide analogues, indicating that the phenolate anion of coelenteramide is the light-emitter in aequorin bioluminescence. (C) 1998 Elsevier Science Ltd. All rights reserved.
Scientific journal, English

A novel, stereoselective photo-Ritter reaction of 1,1-diphenyl-1,6-heptadiene via photoindnced electron transfer reaction
H Ishii; T Hirano; S Maki; H Niwa; M Ohashi
Tetrahedron Letters, PERGAMON-ELSEVIER SCIENCE LTD, 39, 18, 2791-2792, Apr. 1998, Peer-reviwed, True, Irradiation of a wet acetonitrile nitrile solution of 1,1-diphenyl-1,6-heptadiene in the presence of 1,4-dicyanobenzene and phenanthrene provided cis-1-acetamido-3-(diphenylmethyl)cyclohexane in high yields with high stereoselectivity. Several examples leading to cis-1-acylamino-3-(diphenylmethyl)cyclohexanes were also described. (C) 1998 Elsevier Science Ltd. All rights reserved.
Scientific journal, English

Synthesis of（±）-Isoitalicene using Electrolysis under Irradiation as a Key Step.
Yasuhiro Hrada; Shojiro Maki; Takashi Hirano; Haruki Niwa; Shosuke Yamamura
Synlett, Thieme, 12, 1313-1314, 1998, Peer-reviwed, True, By utilizing electrolysis under irradiation, isoitalicene possessing a unique tricyclo [5.4.0.01,5] undec-8-ene skeleton was efficiently synthesized in high yield from a phenol derivative bearing an olefinic side chain.
Scientific journal, English

Substituent effects on the chemiluminescent properties of coelenterazine analogues
R Saito; T Hirano; H Niwa; M Ohashi
Chemistry Letters, CHEMICAL SOC JAPAN, 1, 95-96, 1998, Peer-reviwed, True, Chemiluminescence maxima and quantum yields sf coelenterazine analogues possessing a substituent R [= CF3, F, H, OCH3, OH, N(CH3)(2)] at the para-position on the 6-phenyl group were measured in DMSO, The result indicates that the variation of the electronic properties of R of these analogues caused the small change of the efficiency of chemical generation of a singlet excited light-emitter (Phi(S)).
Scientific journal, English

FAB-CID Mass Spectrometry of Imidazolone Derivatives Related to the Chromophore of Aequorea Green Fluorescent Protein(共著)
Hiraki, T; Kubota, M; Hirano, T; Niwa, H; Ohashi, M
J. Mass Spectrom. Soc. Jpn., Mass Spectrometry Society of Japan, 46, 1, 37-43, 1998, Peer-reviwed, True, Positive and negative ion fast atom bombardment tandem mass spectrometry (FAB-CID MS/MS) has established the fragmentation pattern of the 18 imidazolone derivatives which are related to the structure of the GFP (green fluorescent protein) chromophore in the jellyfish Aequorea bioluminescence. Ring cleavage of the C5-N1 and C2-N3 bonds is characteristics of these compounds, but for NH derivatives cleavage of the methylidene group as well as the C4-C5 and C2-N3 bonds also occurred in the positive ion mode, while ring cleavage of the C2-N3 and C4-C5 bonds occurred commonly in the negative ion mode. On the basis of the CID-MS/MS (collision induced dissociation tandem mass spectrometry) the structures of protonated molecules produced upon FAB are discussed.
When the structure of the fragment ion has a p-quinonoid moiety, distinct peaks due to radical anion species such as [M-H-CH₃]^-· are observed in their CID-MS/MS of parent anions [M-H]^-, which seems to be characteristics of the conjugated p-hydroxyphenyl structures.
Scientific journal, English

Facile cleavage reactions of styrylic olefins using electrochemical methods
S Maki; H Niwa; T Hirano
Synlett, GEORG THIEME VERLAG, 12, 1385-1386, Dec. 1997, Peer-reviwed, True, Negative constant current electrolysis of styrylic olefins in an aqueous solvent resulted in the oxidative cleavage of the double bonds, giving carbonyl compounds in good yields. The double bond conjugated with more than one aromatic ring was selectively cleaved.
Scientific journal, English

Chemi- and bioluminescence of coelenterazine analogues possessing an adamantylmethyl group
T Hirano; R Negishi; M Yamaguchi; FQ Chen; Y Ohmiya; FI Tsuji; M Ohashi
Lead, Tetrahedron, PERGAMON-ELSEVIER SCIENCE LTD, 53, 38, 12903-12916, Sep. 1997, Peer-reviwed, True, with international co-author(s), Coelenterazine analogues possessing the adamantylmethyl group at the C2 or C8 position were prepared to study their effects on chemi-and bioluminescence. Stability of the excited state coelenteramide analogues was significantly affected by the substitutions, resulting in a neutral amide emission of chemiluminescence in diglyme-acetate buffer and in a blue-shifted emission of bioluminescence in Tris-HCl buffer. Substitution of the adamantylmethyl group in the C8 position caused bioluminescence intensity to double. The 8-adamantylmethyl group may serve to orient the coelenterazine skeleton in a suitable position in the active site for efficient bioluminescence activity. Results with semi-synthetic AQs containing 8-adamantylmethyl analogues, and those of semi-synthetic AQs containing 2-benzyl and 2-methyl analogues, indicate that apoAQ and apoAQ C145,152,180S have the ability to recognize the C2 and C8 side-chains in coelenterazine during AQ regeneration. (C) 1997 Elsevier Science Ltd.
Scientific journal, English

Solvent and substituent effects on the fluorescent properties of coelenteramide analogues
R Saito; T Hirano; H Niwa; M Ohashi
Journal of the Chemical Society-Perkin Transactions 2, ROYAL SOC CHEMISTRY, 9, 1711-1716, Sep. 1997, Peer-reviwed, True, Coelenteramide 1 is the light emitter in aequorin bioluminescence. To establish the fluorescent character of 1, the fluorescence properties of 1 and a series of its analogues, 3a-f, possessing a substituent R [= CF3, F, H, OCH3, OH, N(CH3)(2)] at the para-position on the 5-phenyl group have been investigated in solvents of various polarity. The fluorescence emission maxima of 1 and 3d-f, possessing an electron-donating group R [= OCH3, OH, N(CH3)(2)] shift to lower energy with increasing solvent polarity, while those of the analogues 3a-c (R = CF3, F, H) are independent of the solvent polarity. The linear correlation between the fluorescence maxima of 1 and 3d-f and the solvent polarity scales can be explained by formation of the singlet excited state with a charge-transfer (CT) character. The quantum yields of CT fluorescence of 1 and 3d-f have been found to be higher than those of 3a-c. These results indicate that the solvatochromic fluorescence of 1 originates from the CT excited state and the existence of an electron donating hydroxy group on the 5-phenyl group is essential for determining a wavelength and a high fluorescence quantum yield of aequorin bioluminescence.
Scientific journal, English

Abnormal reactivity of anisatin and neoanisatin to samarium iodide hexamethylphosphorictriamide
K Obitsu; S Maki; H Niwa; T Hirano; M Ohashi
Tetrahedron Letters, PERGAMON-ELSEVIER SCIENCE LTD, 38, 23, 4111-4112, Jun. 1997, Peer-reviwed, True, Reactions of anisatin and neoanisatin with SmI2 in the presence of HMPA give novel products having an oxaadamanthane skeleton accompanied by decarboxylation from the spiro beta-lactone functionality. (C) 1997 Elsevier Science Ltd.
Scientific journal, English

Mechanism of the redox reaction of the Aequorea green fluorescent protein (GFP)
S Kojima; T Hirano; H Niwa; M Ohashi; S Inouye; FL Tsuji
Tetrahedron Letters, PERGAMON-ELSEVIER SCIENCE LTD, 38, 16, 2875-2878, Apr. 1997, Peer-reviwed, True, with international co-author(s), A model compound, 4-(4-hydroxyphenyl)methylideneimidazol-5-one undergoes a reversible redox reaction identical to that of the Aequorea green fluorescent protein (GFP), strongly suggesting that the GFP chromophore is derived via the autoxidation of a nonfluorescent dihydro precursor in dihydro-GFP. (C) 1997 Elsevier Science Ltd.
Scientific journal, English

Phytochrome Photochromism Probed by Site-Specific Mutations and Chromophore Esterification
Bhoo, S. H; Hirano, T; Jeong, H. G; Lee, J. G; Furuya, M; Song. P. S
J. Am. Chem. Soc., American Chemical Society, 119, 48, 11717-11718, 1997, Peer-reviwed, True, with international co-author(s)
Scientific journal, English

Chemical nature of the light emitter of the Aequorea green fluorescent protein
H Niwa; S Inouye; T Hirano; T Matsuno; S Kojima; M Kubota; M Ohashi; FI Tsuji
Proceedings of the National Academy of Sciences of the United States of America, NATL ACAD SCIENCES, 93, 24, 13617-13622, Nov. 1996, Peer-reviwed, True, with international co-author(s), The jellyfish Aequorea victoria possesses in the margin of its umbrella a green fluorescent protein (GFP, 27 kDa) that serves as the ultimate light emitter in the bioluminescence reaction of the animal, The protein is made up of 238 amino acid residues in a single polypeptide chain and produces a greenish fluorescence (lambda(max) = 508 nm) when irradiated with long ultraviolet light. The fluorescence is due to the presence of a chromophore consisting of an imidazolone ring, formed by a post-translational modification of the tripeptide -Ser(65)-Tyr(66)-Gly(67)-. GFP has been used extensively as a reporter protein for monitoring gene expression in eukaryotic and prokaryotic cells, but relatively little is known about the chemical mechanism by which fluorescence is produced, To obtain a better understanding of this problem, we studied a peptide fragment of GFP bearing the chromophore and a synthetic model compound of the chromophore, The results indicate that the GFP chromophore consists of an imidazolone ring structure and that the light emitter is the singlet excited state of the phenolate anion of the chromophore, Further, the light emission is highly dependent on the microenvironment around the chromophore and that inhibition of isomerization of the exo-methylene double bond of the chromophore accounts for its efficient light emission.
Scientific journal, English

Shining the light: The mechanism of the bioluminescence reaction of calcium-binding photoproteins
Y Ohmiya; T Hirano
Chemistry & Biology, CURRENT BIOLOGY LTD, 3, 5, 337-347, May 1996, Peer-reviwed, True, The Ca2+-binding photoproteins from jellyfish have the unique ability to emit blue light in the presence of calcium ions but without molecular oxygen or any other cofactor. Although there is no crystallographic data on the structure of the photoprotein complex, structure-activity studies have elucidated many features of the complex and many aspects of the mechanism of the bioluminescence reaction.
Scientific journal, English

The structural origin of the color differences in the bioluminescence of firefly luciferase
Y Ohmiya; T Hirano; M Ohashi
FEBS Letters, ELSEVIER SCIENCE BV, 384, 1, 83-86, Apr. 1996, Peer-reviwed, True, Six chimeric mutants between Hotaria parvula (lambda max=568 mm) and Pyrocoelia miyako (lambda max=550 nm) luciferases were reconstructed to determine the structural origin of the color differences in firefly luciferase. Based on light-emitting color, five chimeric luciferases could be divided into two groups: the three green-emitting mutants, classified as P. miyako luciferase, and the two yellow-emitting mutants, classified as H. parvula luciferase. Their common fragments between Val-209 and Ala-318 within each group contain the active site for the color differences.
Scientific journal, English

Mass Spectrometric Investigation of Stracture of Intermediates in Acridine Chemilumiuescance (共著)
Matsuno, T; Hirano, T; Ohashi, M
Journal of Mass Spectrometry Society of Japan, The Mass Spectrometry Society of Japan, 44, 2, 175-181, 1996, Peer-reviwed, True, Liquid secondary ionization mass spectra (LSIMS) of methylsulfate salts of phenyl, isopropyl, and methyl 10-methyl-acridinium-9-carboxylate were examined under chemiluminescent conditions. Under chemiluminescence conditions, oxygenated acrydinium ions [M + 16]⁺ were observed, whose structures were elucidated as 9-oxy derivatives on the basis of their fragmentation processes obtained by linked scanning at constant B/E. The oxygenated ions are probably derived from the mass spectrometric reaction of the hydroperoxy intermediates in the chemiluminescence proposed by McCapra.
Scientific journal, English

A Potential Photoaffinity Probe for Labelling the Active Site of Aequorin : A Photolabile Coelenterazine Analogue with A Triflusromethyl-diazine Group
Chen, F. Q; Zheng, J. L; Hirano, T; Niwa, H; Ohmiya, Y; Ohashi, M
Journal of Chemical Society, Perkin Transaction 1, ROYAL SOC CHEMISTRY, 17, 2129-2134, Sep. 1995, Peer-reviwed, True, In order to clarify the active site of aequorin, we have: successfully synthesized a photolabile analogue of coelenterazine with a trifluoromethyldiazirine group as a photoaffinity probe. Our studies on the chemi- and bio-luminescence of this novel analogue indicate that its behaviour is almost identical with that of natural coelenterazine in terms of luminescence characteristics. Therefore, the analogue with the photolabile diazirine should be a useful photoaffinity label for probing the detailed structure of aequorin.
Scientific journal, English

Chemi-and Bioluminescent Properties of Coelenterazine Analogues Possessing an Adamantyl Group
Hirano, T; Negishi, R; Yamaguchi, M; Chen, F. Q; Ohmiya, Y; Tsuji, F. I; Ohashi, M
Lead, Journal of Chemical Society, Chemical Communications, ROYAL SOC CHEMISTRY, 13, 1335-1336, Jul. 1995, Peer-reviwed, True, with international co-author(s), The chemi- and bio-luminescent properties of coelenterazine analogues processing either 2- or 8-adamantylmethyl groups are studied and it is found that the bioluminescent intensity of semi-synthetic AQ and AQC145, 152, 180S containing an 8-adamantylmethyl coelenterazine analogues is stronger than that of natural coelenterazine.
Scientific journal, English

FAB CID-MS/MS Characterization of Tetrasaccharide tri-and tetrasulbate Derived from the Antigenic Determinant Recognized by the Anti-chondroitin sulfate Monoclonal Antibody MO-225
Ii, T; Kubota, M; Hirano, T; Ohashi, M; Yoshida, K; Suzuki, S
Glycicinjugate Journal, CHAPMAN HALL LTD, 12, 3, 282-289, Jun. 1995, Peer-reviwed, True, The fast atom bombardment (FAB) collision induced dissociation (CID)-mass spectometry/mass spectrometry (MS/MS) technique was successfully applied to characterize and identify the structures of the immunoreactive trisulfated and tetrasulfated tetrasaccharides that were obtained from the chondroitin sulfate in a shark fin using a treatment with chondroitinase ABC.
Scientific journal, English

Negative-ion fast atom bombordment tandem mass spectrometry for characterization of sulfated unsaturated disaccharides from heparin and heparan sulfate
Ii, T; Kubota, M; Okuda, S; Hirano, T; Ohashi, M
Glycoconjugste Journal, CHAPMAN HALL LTD, 12, 2, 162-172, Apr. 1995, Peer-reviwed, True, Negative-ion fast atom bombardment tandem mass spectrometry has been used in the characterization of non-, mono-, di- and trisulfated disaccharides from heparin and heparan sulfate. The positional isomers of the sulfate group of monosulfated disaccharides were distinguished from each other by negative-ion fast atom bombardment tandem mass spectra, which provide an easy way of identifying the positional isomers. This fast atom bombardment collision induced dissociation mass spectrometry/mass spectrometry technique was also applied successfully to the characterization of di- and trisulfated disaccharides.
Scientific journal, English

Positive-ion fast atom bombordment tandem mass spectrometry for characterization of sulfated unsaturated disaccharides from heparin and heparan sulfate
Ii, T; Kubota, M; Okuda, S; Hirano, T; Ohashi, M
European Journal of Mass Spectrometry, IM PUBLICATIONS, 1, 1, 11-22, Jan. 1995, Peer-reviwed, True, Positive-ion fast atom bombardment tandem mass spectrometry has been used in the characterization of non-, mono-, di- and trisulfated disaccharides from heparin and heparan sulfate, The positional isomers of sulfate groups of monosulfated disaccharides have been distinguished from each other by positive-ion fast atom bombardment tandem mass spectra, which provide an easy way of identifying the positional isomers. The fast atom bombardment collision-induced dissociation mass spectrometry/mass spectrometry technique was also applied successfully to the characterization of di- and trisulfated disaccharides.
Scientific journal, English

Synthesis and Preliminary Chemi-and Bio-luminescence Studies of a novel Photolabile Coelenterazine Analogue with a Trifluoro methyl Diazirine Group
Chen, F. Q; Hirano, T; Hashizume, Y; Ohmiya, Y; Ohashi, M
Journal of Chemical Society, Chemical Communications, ROYAL SOC CHEMISTRY, 20, 2405-2406, Oct. 1994, Peer-reviwed, True, A novel photolabile analogue of coelenterazine with a trifluoromethyl diazirine group is successfully synthesized for photoaffinity labelling of the active site of aequorin; preliminary studies on its chemi- and bio-luminescence demonstrate that the photolabile analogue shows the same luminescence properties and kinetics as those of natural coelenterazine and thus, it is deduced that both compounds occupy the same active site; of aequorin.
Scientific journal, English

Tandem mass spectrometry for cheracterization of unsaturated disaccharides for chondroitin sulfate, dermatan sulfate and hyaluronan
Ii, T; Okuda, S; Hirano, T; Ohashi, M
Glycoconjugate Journal, CHAPMAN HALL LTD, 11, 2, 123-132, Apr. 1994, Peer-reviwed, True, Fast atom bombardment tandem mass spectrometry has been used in the characterization of non-, mono-, di- and trisulfated disaccharides from chondroitin sulfate, dermatan sulfate and hyaluronan. The positional isomers of the sulfate group of mono- and disulfated disaccharides were distinguished from each other by both positive- and negative-ion fast atom bombardment tandem mass spectra, which gave sufficient information characteristic of the isomers. The anomeric isomers of nonsulfated disaccharides were characterized by the technique in the positive-ion mode. This fast atom bombardment collision induced dissociation mass spectrometry/mass spectrometry technique was also applied successfully to the characterization of trisulfated disaccharide.
Scientific journal, English

Revision of the Structure of the Light-emitter in Aeguorin Bioluminescence
Hirano, T; Mizoguchi, I; Yamaguchi, M; Chen, F. Q; Ohashi, M; Ohmiya, Y; Tsuji, F. I
Lead, Journal of Chemical Society, Chemical Communications, ROYAL SOC CHEMISTRY, 2, 165-167, Jan. 1994, Peer-reviwed, True, with international co-author(s), The structure of the excited light-emitter in aequorin bioluminescence was assigned not to an amide anion of coelenteramide but to a phenolate anion on the basis of the luminescence of regenerated aequorin and of the fluorescence of regenerated blue fluorescent protein with coelenteramide analogues including N-methyl derivatives.
Scientific journal, English

Mass Spectrometric Studies on Chemiluminescence of Coelenterate Luciferin Analoques
Hirano, T; Nishibuchi, S; Yoneda, M; Tujimoto, K; Ohashi, M
Lead, Tetrahedron, PERGAMON-ELSEVIER SCIENCE LTD, 49, 41, 9267-9276, Oct. 1993, Peer-reviwed, True, Electron ionization (EI) and liquid secondary ionization mass spectra (LSIMS) of 30 coelenterazine analogues were examined by use of linked scanning at constant B/E and the fragmentation rules upon EI and LSIMS have been established. On the basis of these results the structures of intermediates in the chemiluminescence of these compounds have been deduced as monooxygenated compounds and the possible mechanisms of chemiluinescence of these compounds are discussed.
Scientific journal, English

Secondary Ion Mass Spectrometry of Sugar Nucleotides
Ii, T; Okuda, S; Hirano, T; Tsujimoto, K; Ohashi, M
Organic Mass Spectrometry, JOHN WILEY & SONS LTD, 28, 2, 127-131, Feb. 1993, Peer-reviwed, True, Secondary ion mass spectra of fifteen sugar nucleotide sodium salts were investigated. In the negative-ion mode, deprotonated free acid molecules, desodiated sodium salts and some structurally significant fragment ions were obtained. The linked scan at constant B/E gave information on the characteristics of the sugar, nucleosides and base moieties in the sugar nucleotides.
Scientific journal, English

3-Benzyl-5-(4-hydroxyphenyl)-2-[4-(1-azi-2,2,2-tribluoroethyl) phenylacetamido] pyrazine, a Photoreactive Analogue of Coelenteramide, Synthesis and Photolysis
Chen, F. Q; Hirano, T; Ohashi, M; Nakayama, H; Oda, K; Machida, M
Chemistry Letters, CHEMICAL SOC JAPAN, 2, 287-290, Feb. 1993, Peer-reviwed, True, A photoreactive analogue of coelenteramide (light emitting species in aequorin bioluminescence) has been synthesized for photoaffinity labeling studies of aequorin. Photolysis of this compound in methanol gave a formal OH insertion product in 62% yield without damage of the main skeleton of coelenteramide, indicating a potential use for mapping the coelenterazine binding site in aequorin.
Scientific journal, English

Characterization of Positional and Anomeric Isomers of Methyl 2-0-and 3-0-Sulto-D-glucopyranosiduronic Acids and Methyl 2-0-and 3-0-Sulfo -D-glucopyranosides by Secondary Ion Mass Spectrometry
Ii, T; Okuda, S; Hirano, T; Tsujimoto, K; Ohashi, M
Oraganic Mass Spectrometry, 28, 789-794, 1993, Peer-reviwed, True, Secondary ion mass spectrometry (SIMS) of anomeric pairs of methyl 2-O- and 3-O-sulfo-D-glucopyranosiduronic acids and methyl 2-O- and 3-O-sulfo-D-glucopyranosides show the deprotonated molecule in the negative-ion mode and ammoniated and sodiated molecules in the positive-ion mode. The four isomers were distinguished from each other by linked scanning at constant B/E in negative- and positive-ion SIMS, which gave information characteristic of the position of the sulfate group and even the configuration of the anomeric methoxy group. The main fragmentation processes correspond to the loss of methanol and the elimination of SO3.
Scientific journal, English

Mass Spectrometry of Charge-transfer Complexes of 7,7', 8,8'-Tetracyano guinodimethome-π-Donor Systems
Kurono, S; Tani, T; Hirano, T; Tsujimoto, K; Ohashi, M
Organic Mass Spectrometry, JOHN WILEY & SONS LTD, 27, 12, 1365-1369, Dec. 1992, Peer-reviwed, True, Electron impact (EI) ionization and positive and negative liquid secondary ion mass spectrometry (pLSIMS and nLSIMS) of eight charge-transfer complexes of 7,7',8,8'-tetracyanoquinodimethane (TCNQ)-aromatic systems and of the individual pi-donors and -acceptors was examined. The EI spectra exhibited the molecular ions of both the donor and the acceptor of each complex. The molecular ion of the pi-donor was observed in pLSIMS using m-nitrobenzyl alcohol (NBA) if its oxidation potential is lower than 1.2 V, but when the oxidation potential is higher than 1.9 V, no molecular ion was detected. On the other hand, nLSIMS exhibited the molecular ion of TCNQ in all cases. Participation of an excited state of NBA in the ionization process is suggested.
Scientific journal, English

Photoinduced electron-transfer reaction of 7-benzhydrylidenenorbornene - Chemical capture of a radical cation intermediate with nonclassical cation character
T Hirano; S Shiina; M Ohashi
Lead, Journal of the Chemical Society-Chemical Communications, ROYAL SOC CHEMISTRY, 21, 1544-1545, Nov. 1992, Peer-reviwed, True, A photoinduced electron-transfer reaction of benzhydrylidenenorbornene 1 as an electron donor gives the radical cation 1+., which could be captured chemically by methanol or by the intramolecular hydroxy group, indicating the existence of a strong homoconjugative interaction between the exocyclic double bond and the C(2)-C(3) double bond.
Scientific journal, English

Detection of molecule-ions of cyclodextrin inclusion complexes
S Kurono; T Hirano; K Tsujimoto; M Ohashi; M Yoneda; Y Ohkawa
Organic Mass Spectrometry, JOHN WILEY & SONS LTD, 27, 10, 1157-1160, Oct. 1992, Peer-reviwed, True
Scientific journal, English

Chemiluminescence of coelenterazine analogues - structures of emitting species -
Takashi Hirano; Yasushiro Gomi; Tomoyuki Takahashi; Kennichi Kitahara; Chen Feng Qi; Iwao Mizoguchi; Soichiro Kyushin; Mamoru Ohashi
Lead, Tetrahedron Letters, Elsevier BV, 33, 39, 5771-5774, Sep. 1992, Peer-reviwed, True
Scientific journal

Chemi- and bio-luminescence of coelenterazine analogues with phenyl homologues at the C-2 position
Chen Feng Qi; Yasushiro Gomi; Takashi Hirano; Mamoru Ohashi; Yoshihiro Ohmiya; Frederick I. Tsuji
Journal of the Chemical Society, Perkin Transactions 1, Royal Society of Chemistry (RSC), 13, 1607-1607, Jul. 1992, Peer-reviwed, True
Scientific journal

Inversion of the ground-state spin multiplicity by electron-withdrawing groups in trimethylenemethane derivatives generated photochemically from methylenequadricyclane derivatives
T Hirano; T Kumagai; T Miyashi; K Akiyama; Y Ikegami
Lead, Journal of Organic Chemistry, AMER CHEMICAL SOC, 57, 3, 876-882, Jan. 1992, Peer-reviwed, True, An inversion of the ground-state spin multiplicity of trimethylenemethane (TMM) by electron-withdrawing groups was investigated by EPR spectroscopy, for a series of TMMs 2b-g generated photochemically from methylenequadricyclanes 1b-g. Curie law analyses between 4 and 50 K proved the triplet ground states of the monophenyl derivative 2b and the monocyano derivatives 2c-d as well as that of the diphenyl derivative 2a. The dicarbomethoxy derivative 2e also exhibited the EPR signal, but the Curie plot was nonlinear and the signal disappeared irreversibly above 10K. The triplet ground state was inverted to the singlet by the carbomethoxy-cyano and dicyano substitutions, and 2f and 2g were EPR silent species similar to the singlet oxyallyl (OA) derivative 2h. The singlet ground state of 2g was demonstrated by its chemical behaviors which resemble those of 2h.
Scientific journal, English

Novel photoreactions of benzhydrylidenequadricyclane and quadricyclanone: a new route to trimethylenemethane and oxyallyl derivatives
T Hirano; T Kumagai; T Miyashi; K Akiyama; Y Ikegami
Lead, Journal of Organic Chemistry, AMER CHEMICAL SOC, 56, 5, 1907-1914, Mar. 1991, Peer-reviwed, True, The irradiation of 3-benzhydrylidenequadricyclane (1) generated a trimethylenemethane (TMM) derivative, 3-benzhydrylidenebicyclo[3.2.0]hept-6-ene-2,4-diyl (3), which dimerized and could be chemically captured by molecular oxygen and acrylonitrile, but not by furan, methanol, or ethyl vinyl ether. The triplet nature of 3 was confirmed by EPR, emission, and absorption spectra. By contrast, the irradiation of quadricyclanone (2) generated the singlet oxyallyl (OA), 3-oxobicyclo[3.2.0]hept-6-ene-2,4-diyl (4) which could be captured by furan, methanol, and ethyl vinyl ether, but not by molecular oxygen or acrylonitrile, indicating the zwitterionic and electron-accepting nature of 4.
Scientific journal, English

ホタルの発光する仕組み
平野 誉
岩波書店, 01 May 2024, 科学（特集：魅惑の発光生物）, 94, 5, 453-457, Japanese, Peer-reviwed, Invited, Introduction commerce magazine, False

化学の本だな「”恐竜はホタルを見たか-発光生物が照らす進化の謎-”，大場裕一著」書評
平野 誉
Corresponding, 生物発光研究の若手研究者である大場裕一先生の著書”恐竜はホタルを見たか-発光生物が照らす進化の謎-”の書評。, 化学同人, 01 Sep. 2016, 化学, 71, 9, 53-53, Japanese, Invited, Book review

化学発光と生物発光の基礎化学
平野 誉
Corresponding, 化学発光と生物発光の反応機構の最新情報について、高校教員を対象とするわかりやすい内容にて総合的に解説した。, 日本化学会, 20 Aug. 2016, 化学と教育, 64, 8, 376-379, Japanese, Peer-reviwed, Invited, Introduction scientific journal, False, 0386-2151, 40020942041, AN10033386

Chemistry of firefly bioluminescence: Frontiers in fundamental and application researches
平野 誉
Corresponding, ホタル生物発光の化学的研究の基礎と応用について、著者らの研究も交えて最新の状況を解説した。, 光化学協会, 20 Apr. 2015, 光化学（光化学協会会誌）, 46, 1, 21-28, Japanese, Invited, Introduction scientific journal, False, 0913-4689, 40020462331, AN10131680

バイオルミネッセンス化学の基礎と展開（特集／ルミネッセンス化学の最前線）
平野 誉
Corresponding, 化学工業社, 01 May 2014, 化学工業, 65, 5, 43-49, Japanese, Invited, Introduction commerce magazine, 0451-2014

The reaction mechanism of calcium-activated photoprotein bioluminescence
Takashi Hirano
Lead, Calcium-activated photoproteins are important and useful bioluminescent reagents for detecting the calcium ion (Ca2+) in biological systems. In conjunction with photon imaging technology, they can be used to observe Ca2+-related life processes in a living cell. To develop useful applications of calcium-activated photoproteins, we need to understand the molecular basis of the bioluminescence reaction. For this purpose, this review describes the oxygenation, chemiexcitation, and light emission processes of calcium-activated photoproteins in the bioluminescence reaction together with the fundamental chemistry of the luminous substrate, coelenterazine, based on recent results from mechanistic chemical studies of these primary processes. Finally, the whole reaction mechanism, including the active site structures of apoproteins, along with available information about the molecular mechanism and the crystallographic structures of calcium-activated photoproteins are summarized. © 2012 Bentham Science Publishers., Bentham Science Publishers B.V., 2012, Current Pharmaceutical Biotechnology, 13, 14, 2551-2561, English, Peer-reviwed, Introduction scientific journal, True, 1873-4316, 84872531903

Design of light-emitting molecular devices based on bioluminescence reaction mechanism
平野 誉
Corresponding, 広信社, Jun. 2009, 表面, 47, 6, 202-211, Japanese, Introduction commerce magazine, False, 0367-648X, 40016709422, AN00211091

developments of the studies on the reaction mechanism of Vargula (Cypridina) and Aequorea bioluminescence
平野 誉
Aug. 2007, 光化学（光化学協会誌）, 38, 2, 111-118, Japanese, Peer-reviwed, Introduction scientific journal, False

分子イメージング最前線～いま注目の論文「生物発光とナノテクの融合－生体内イメージングのための自家発光量子ドット」
平野 誉; 化学同人編集部
Corresponding, Apr. 2007, 別冊化学「分子イメージング－蛍光プローブが拓くライフサイエンスの未来」, 89-91, Japanese, Introduction other

生物発光分子系を基盤とする機能性色素化学：イミダゾピラジノンπ電子系の基礎化学と応用
平野 誉
Corresponding, The imidazo [1, 2-a] pyrazin-3 (7H) -one (imidazopyrazinone) ring is a core structure of the luminescent substrates isolated from marine bioluminescent organisms, such as the crustacean Vargula (Cypridina) and the jellyfish Aequorea. To develop the bioluminescence chemistry, we revealed the unique π-electronic character of the imidazopyrazinone ring system on the basis of the pioneering study by Goto et al. In this article, we provide an overview of the fundamental chemistry of imidazopyrazinone including the molecular structure, aromaticity of the π-system, molecular orbital, solvatochromism, acid-base behavior, tautomerism, and electron-donating ability. Especially, the imidazopyrazinone π-system having a twitterionic character is sensitively affected by a microenvironment around molecules, to show a continuous absorption-spectral change. Therefore, imidazopyrazinones are useful as functional dyes to indicate a magnitude of an interaction with a microenvironment, such as a hydrogen bond and a Lewis acid-base interaction. We also describe applications of imidazopyrazinone derivatives as indicators for naked eye detection of the hydrogen-bond donor strength of a solvent molecule, the Lewis acidity of a metal ion, and a hydrophobic interaction with a protein., The Society of Synthetic Organic Chemistry, Japan, Oct. 2006, 有機合成化学協会誌, 64, 10, 1062-1072, Japanese, Peer-reviwed, Introduction scientific journal, False, 0037-9980, 10018311691, AN0024521X

Luciferin chiral selectivity divides action mode of firefly luciferase: L-selective coenzyme A ligation and D-selective bioluminescence.
Mitsuhiro Nakamura; Shojiro Maki; Yoshiharu Amano; Yutaka Ohkita; Kazuki Niwa; Takashi Hirano; Yoshihiro Ohmiya; Haruki Niwa
Jun. 2005, Biochemical and Biophysical Research Communications, 331, 471-475

生物発光研究からの分子素子開発の展望（特集／分子エレクトロニクスの展望）
平野 誉
Corresponding, 化学工業社, 01 Aug. 2001, 化学工業, 52, 8, 622-627, Japanese, Invited, Introduction commerce magazine, False, 0451-2014, 40000415838, AN00037245

部位特異的変異法
大橋 守; 平野 誉
01 Jul. 1996, 有機合成化学協会誌, 54, 7, 623-623, Japanese, 0037-9980, 10001840461, AN0024521X

オワンクラゲ生物発光の分子過程-化学発光・生物発光における励起分子生成機構(共著)
平野 誉; 大橋 守
1996, 有機合成化学協会誌, 54, 7, 596-606, Japanese, Introduction other

生物発光と化学発光の分子機構
平野 誉; 大橋 守
Lead, 1993, 化学と生物, 31, 3, 195-200, Japanese, Peer-reviwed, Introduction scientific journal, False

Soft Crystals - Flexible Response Systems with High Structural Order (The Materials Research Society Series)
Hirano, T; Matsuhashi, C
English, Contributor, Soft Crystal Chemiluminescence Systems Using Organic Peroxides, 265, 155-177, Springer Singapore, 27 Mar. 2023, Peer-reviwed, 9789819902606

CSJ Current Review 36, 「生体分子反応を制御する－化学的手法による機構と反応場の解明」
日本化学会編; 執筆者の一人として
Scholarly book, Japanese, Contributor, ”10章 生物発光反応の制御方法” 担当, 212, 101-106, 化学同人, 30 Mar. 2020, Peer-reviwed, 9784759813968, 生体反応に関する最新の研究を概説した教科書。この中で、生物発光の基礎と最先端応用について解説した。

光化学フロンティア－未来材料を生む有機光化学の基礎
水野一彦; 宮坂 博; 池田 浩; 編
Scholarly book, Japanese, Contributor, 第１５章 光生命科学, 400, 349-362, 化学同人, 30 Dec. 2018, Peer-reviwed, 9784759814194, 有機光化学の基礎から応用の最先端を解説した教科書。この中で、生物発光を含め、生命科学に関わる光化学について解説した。

光と生命の事典
日本光生物学協会; 光と生命の事典; 編集委員会; 編(執筆者の一人として
Dictionary or encycropedia, Japanese, Contributor, 194「光殺菌作用」, 朝倉書店, 25 Feb. 2016, 9784254171617, 光と生命に関連する事項や現象を化学、生物学、医学などの分野から解説した辞典。基礎理論から応用・実用的な内容までを解説。この中で、光殺菌作用について解説した。

有機合成実験法ハンドブック 第2版
有機合成化学協会編集; 中井武編集代表; 執筆者の一人として
Dictionary or encycropedia, Japanese, Contributor, 色素増感酸素酸化反応とその応用, 丸善, 28 Nov. 2015, 9784621089484, 有機合成における実験の基本と実験技術など実践的内容からなる、有機合成を行う学生から研究者に役立つ標準的実験書。この中で、光化学反応の解説を行った。

光化学の事典
光化学協会; 執筆者の一人として参加; 光化学の事典編集委員会
Dictionary or encycropedia, Japanese, Contributor, ８章「光と生物・生化学」、8.1「生物の光吸収、蛍光と発光」、「⑤ルシフェリン」316-317頁, 朝倉書店, 01 Jun. 2014, 9784254140965, エネルギーから医療への応用まで，人類社会への新たな貢献が期待される「光化学」の幅広い可能性を解説した事典の中で、生物発光に関わるルシフェリンの解説を行った。

Proceedings of the 15th International Symposium on Bioluminescence and Chemiluminescence: Light Emission: Biology and Scientific Applications
T. Hirano; H. Ohba; Y. Takahashi; S. Maki; S. Kojima; H. Ikeda; H. Niwa
English, Joint work, Chemiexcitation Mechanism for Cypridina (Vargula) and Aequorea Bioluminescence, 19-22, World Scientific, Dec. 2008, Peer-reviwed

Proceedings of the 14th International Symposium on Bioluminescence and Chemiluminescence: Chemistry, Biology and Applications
T. Hirano; Y. Takahashi; H. Kondo; H. Ikeda; S. Maki; H. Niwa
English, Joint work, Mechanistic Study on the Cypridina (Vargula) Bioluminescence Reaction, 11-14, World Scientific, 2007, Peer-reviwed

Bioluminescence & Chemiluminescence Progress and Perspectives
T. Hirano; S. Nakai; T. Sekiguchi; S. Fujio; S. Maki; H. Niwa
English, Joint work, Development of the Chemistry of the Imidazopyrazinone-bioluminescence System: From the Bio- and chemiluminescence Mechanism to a Design of Sensor Molecules, 117-120, World Scientific, Mar. 2005, Peer-reviwed

Bioluminescence & Chemiluminescence Progeress and Perspectives
R. Saito; N. Suga; A. Katoh; S. Maki; T. Hirano; H. Niwa
English, Joint work, 6,8-Diarylimidazo[1,2-a]pyrazin-3(7H)-ones as potential chemiluminescent pH/superoxide double sensors, 335-338, World Scientific, Mar. 2005, Peer-reviwed

生物発光・化学発光の分子過程／季刊化学総説「光化学の基礎と最先端研究」
平野 誉; 大橋 守
Scholarly book, Japanese, Joint work, 日本化学会編，学会出版センター, Jun. 1998

Mechanistic study on the firefly bioluminescence reaction based on photochemistry
Takashi Hirano
Invited oral presentation, English, The 31st International Conference on Photochemistry (ICP2023), Invited
24 Jul. 2023
23 Jul. 2023- 28 Jul. 2023

有機光化学で迫る生物発光と化学発光：ホタルからソフトクリスタルへ
平野 誉
Keynote oral presentation, Japanese, 2022年度有機光化学研究会, Invited, 有機光化学研究会実行委員会, 宮城郡松島町, 本学で研究する生物発光と化学発光の研究の面白さと全体の成果を歴史的背景も含めて解説した。, Domestic conference
19 Feb. 2023
19 Feb. 2023- 20 Feb. 2023

ソフトクリスタル化学発光系で築く結晶化学反応の学理
平野 誉
Invited oral presentation, Japanese, 新学術領域研究ソフトクリスタル第８回公開シンポジウム資料集, Invited, 新学術領域研究ソフトクリスタル, 関西学院大学西宮上ヶ原キャンパス, 新学術領域研究の成果をまとめて発表した, Domestic conference
11 Mar. 2022
11 Mar. 2022

Thermal Reaction-induced Phenomena in Soft Crystals Found with 1,2-Dioxetane Chemiluminescence
C. Matsuhashi; H. Oyama; H. Uekusa; H. Fujisawa; M. Ryu; J. Morikawa; A. Sato-Tomita; K. Ichiyanagi; T. Hirano
Invited oral presentation, English, 3rd International Symposium on Soft Crystals jointed with 4th Internal Symposium on Photofunctional Chemistry of Complex Systems and IIS U Tokyo Symposium, Invited, The Photofunctional Complexes Research Association Japan & SOFT CRYSTALS: Science and Photo Functions of Flexible Response Systems with High Order, Hawaii & Online, https://www.eng.hokudai.ac.jp/labo/amc/ISPCCS/invited.html, 光機能を有する化合物とその結晶材料に関する国際会議にて、結晶化学発光に関する招待講演を行った。, International conference
13 Dec. 2021

A Soft-Crystal Chemiluminescence System: Luminescence Property of Adamantylideneadamantane 1,2-Dioxetanes Conjugated with a Fluorophore
C. Matsuhashi; H. Uekusa; K. Ichiyanagi; A. Sato-Tomita; M. Ryu; J. Morikawa; S. Maki; T. Hirano
Invited oral presentation, English, 239th ECS meeting with the 18th International Meeting on Chemical Sensors (IMCS), Invited, The Electrochemical Society, Digital Meeting, https://www.electrochem.org/239, Soft Crystal のテーマによるシンポジウムにて、特任研究員の松橋氏が結晶化学発光の最新成果を招待講演で報告した。, International conference
02 Jun. 2021

Study on Soft-Crystal Chemiluminescence, a Solid-State Chemistry to Support Devise Development
T. Hirano; C. Matsuhashi; F. Koura; S. Maki; H. Uekusa; A. Sato-Tomita; K. Ichiyanagi; M. Ryu; J. Morikawa
Invited oral presentation, English, 239th ECS meeting with the 18th International Meeting on Chemical Sensors (IMCS), Invited, The Electrochemical Society, Digital Meeting, https://www.electrochem.org/239, Soft Crystal のテーマによるシンポジウムにて、結晶化学発光の最新情報を招待講演で報告した。, International conference
02 Jun. 2021

ソフトクリスタル化学発光系による可視化で捉えた結晶内反応の特徴
平野 誉
Invited oral presentation, Japanese, 新学術領域研究ソフトクリスタル第６回公開シンポジウム資料集, Invited, 新学術領域研究ソフトクリスタル, オンライン開催, https://www.softcrystal.org/event/3606, 結晶内での化学発光反応により、光検出で結晶内の反応解析が可能となったことを解説した。, Domestic conference
22 Jan. 2021

ソフトクリスタル化学発光系の創製：結晶内反応の可視化による評価
平野 誉
Nominated symposium, Japanese, 新学術領域研究ソフトクリスタル第5回公開シンポジウム資料集, Invited, 新学術領域研究ソフトクリスタル, 千葉大学工学系総合研究棟, https://www.softcrystal.org/event/2660, 新学術領域研究の計画班として進めている研究の最新データに基づく講演を行った。特に、結晶内反応の可視化の重要性を示した。, Domestic conference
31 Jan. 2020

Recent Advances in Fundamental Chemistry of Bio- and chemiluminescence
Takashi Hirano
Invited oral presentation, English, International Symposium on Circularly Polarized Luminescence and the Related Phenomena, Invited, Professor Ken-ichi Sugiura, Tokyo Metropolitan University, Tokyo Metropolitan University, Akihabara Satellite Campus, https://www.kitasato-u.ac.jp/sci/resea/kagaku/HP_kinou/cpl_2019/index.html, 研究例が急激に増えつつあり、国内の研究が世界をリードする円偏光発光（CPL）の研究者が集まり、情報交換の場を作るために開催された。CPLの関連現象として、生物・化学発光の関心を集めた。, International conference
29 Nov. 2019

Oxygenation Model Reactions of the Firefly Bioluminescence
S. Ito; S. Maki; T. Hirano
Poster presentation, English, Collected Abstract of The Irago Conference 2019, UEC, Chofu, Tokyo, http://iragoconference.jp/archives/2019, ホタル生物発光の酸素化反応機構を解明した。, International conference
29 Oct. 2019

Color Modulation in the Firefly Bioluminescence: Mechanism Elucidation Based on the Fluorescence Property of the Enol-form of Oxyluciferins
S. Hiraga; M. Yamaji; S. Maki; T. Hirano
Poster presentation, English, Collected Abstract of The Irago Conference 2019, UEC, Chofu, Tokyo, http://iragoconference.jp/archives/2019, ホタル生物発光の発光色制御機構を解明した。, International conference
29 Oct. 2019

Crystalline-state Chemiluminescence of 1,2-Dioxetanes with an Phenacene Side Chain
K. Ishitani; C. Matsuhashi; M. Yamaji; H. Uekusa; S. Maki; T. Hirano
Poster presentation, English, Collected Abstract of The Irago Conference 2019, UEC, Chofu, Tokyo, http://iragoconference.jp/archives/2019, 結晶状態の化学発光特性について新しい発光挙動を見出した。, International conference
29 Oct. 2019

色素連結型アダマンチリデンアダマンタン系ジオキセタンの結晶状態での化学発光特性の評価
松橋千尋; 植草秀裕; 佐藤文菜; 牧昌次郎; 平野 誉
Oral presentation, Japanese, 2019年光化学討論会講演要旨集, 光化学協会, 名古屋大, https://photochemistry.jp/2019/gaiyou.html, 異性体で発光特性の異なる結晶化学発光機構を解明した。, Domestic conference
12 Sep. 2019

アクリジン系1,2-ジオキセタン誘導体の結晶状態での化学発光特性
小浦史也; 松橋千尋; 植草秀裕; 牧昌次郎; 平野 誉
Poster presentation, Japanese, 2019年光化学討論会講演要旨集, 光化学協会, 名古屋大, https://photochemistry.jp/2019/gaiyou.html, 反応進行で発光波長の変化する結晶化学発光系を見出した。, Domestic conference
12 Sep. 2019

フェナセン側鎖を有する1,2-ジオキセタンの結晶状態での化学発光：エネルギー移動型発光特性の評価
石谷 薫; 松橋千尋; 山路 稔; 植草秀裕; 平野 誉
Poster presentation, Japanese, 2019年光化学討論会講演要旨集, 光化学協会, 名古屋大, https://photochemistry.jp/2019/gaiyou.html, 結晶の作製条件で発光挙動が異なる結晶化学発光系を見出した。, Domestic conference
12 Sep. 2019

ルシフェリン構造改変に基づくホタル生物発光の反応機構解明
伊藤真一; 牧昌次郎; 平野 誉
Poster presentation, Japanese, 2019年光化学討論会講演要旨集, 光化学協会, 名古屋大, https://photochemistry.jp/2019/gaiyou.html, ホタル生物発光の酸素化反応機構を解明した。, Domestic conference
12 Sep. 2019

ホタル発光系の波長制御機構研究：エノール型発光体の蛍光特性評価
平賀詩織; 山路 稔; 牧昌次郎; 平野 誉
Poster presentation, Japanese, 2019年光化学討論会講演要旨集, 光化学協会, 名古屋大, https://photochemistry.jp/2019/gaiyou.html, ホタル生物発光の発光波長制御機構を解明した。, Domestic conference
12 Sep. 2019

A Soft Crystal Chemiluminescence System: Chemiluminescence Property of 1,2-Dioxetanes with a Phenacene Side-chain in the Crystalline-state,
Kaoru Ishitani; Chihiro Matsuhashi; Minoru Yamaji; Hidehiro Uekusa; Takashi Hirano
Poster presentation, English, The 2nd International Symposium on Soft Crystals (Pre-symposium of ISPPCC2019), Abstract, Soft Crystal Project, Narita, Chiba, http://softcrystal.net/preISPPCC/, 結晶状態でのエネルギー移動型化学発光特性を見出した。, International conference
12 Jul. 2019

Crystalline-state Chemiluminescence Property of Adamantylideneadamantane 1,2-Dioxetanes with a Conjugated Fluorophore
Chihiro Matsuhashi; Hidehiro Uekusa; Ayana Sato-Tomita; Shojiro Maki; Takashi Hirano
Poster presentation, English, The 2nd International Symposium on Soft Crystals (Pre-symposium of ISPPCC2019), Abstract, Soft Crystal Project, Narita, Chiba, http://softcrystal.net/preISPPCC/, 異性体で異なる化学発光特性を示す結晶化学発光機構を解明した。, International conference
12 Jul. 2019

Crystalline-state Chemiluminescence Properties of 1,2-Dioxetane Derivatives with a Acridine Moiety
Fumiya Koura; Chihiro Matsuhashi; Hidehiro Uekusa; Shojiro Maki; Takashi Hirano
Poster presentation, English, The 2nd International Symposium on Soft Crystals (Pre-symposium of ISPPCC2019), Abstract, Soft Crystal Project, Narita, Chiba, http://softcrystal.net/preISPPCC/, 反応進行で発光色が変化する結晶化学発光特性を見出した。, International conference
12 Jul. 2019

Seeing Chemical Reactions in Soft Crystals: Crystalline-state Chemiluminescence Properties of 1,2-Dioxetane Derivatives
Takashi Hirano; Chihiro Matsuhashi; Kaoru Ishitani; Fumiya Koura; Shun Azuma; Shojiro Maki; Hidehiro Uekusa; Ayana Sato-Tomita; Minoru Yamaji
Invited oral presentation, English, The 2nd International Symposium on Soft Crystals (Pre-symposium of ISPPCC2019), Invited, 新学術領域研究「ソフトクリスタル」, 成田, http://softcrystal.net/preISPPCC/, ソフトクリスタル化学発光系の構築について、最新の研究成果を報告した。, International conference
12 Jul. 2019

ソフトクリスタル化学発光系の創製：ジオキセタン系の固相化学発光
平野 誉
Nominated symposium, Japanese, 新学術領域研究ソフトクリスタル第3回公開シンポジウム資料集, Invited, 文部科学省科研費「ソフトクリスタル」, 龍谷大学響都ホール校友会館, 新学術領域研究の研究班として、最新の研究成果を研究背景と共に解説した。, Domestic conference
01 Feb. 2019

反応機構で考える生物・化学発光
平野 誉
Invited oral presentation, Japanese, 生物発光化学発光研究会第３３回学術講演会：未来を照らす発光研究, Invited, 生物発光化学発光研究会, 東邦大学習志野キャンパス, 電通大で取り組んできた生物・化学発光の分子メカニズムの研究をまとめて解説する。, Domestic conference
21 Oct. 2017

Study on the color modulation mechanism of firefly bioluminescence with an amine substituent effect of luciferin and oxyluciferin
M. Kakiuchi; M. Yamaji; S. Maki; T. Hirano
Oral presentation, English, The 2015 International Chemical Congress of Pacific Basin Societies (Pacifichem 2015), BIOL: Luciferin/Luciferase Engineering (#410), Abstract, Pacific Basin Societies of Chemistry, Hawaii, USA, http://www.pacifichem.org/, ホタル生物発光に関わるルシフェリンとオキシルシフェリンの発光特性の光化学的解析の成果発表を行った。, International conference
16 Dec. 2016

The Color Modulation Mechanism in Beetle Bioluminescence Based on Photochemical Evaluations of the Luminescent Properties
T. Hirano; M. Kakiuchi; T. Matsuhashi; S. Maki; M. Yamaji; V. R. Viviani
Invited oral presentation, English, The 19th International Symposium on Bioluminescence & Chemiluminescence (ISBC2016), Invited, International Society of Bioluminescence & Chemiluminescence, つくば市, http://isbc2016.com/, ホタル生物発光の波長制御機構について、分子論の最新データを紹介しながら議論した。, International conference
01 Jun. 2016

Design of Heterocyclic Fluorophores Based on a Bioluminescence Light-emitter
T. Hirano; T. Nakagawa; Y. Suzuki; S. Maki; M. Yamaji
Oral presentation, English, The 26th IUPAC Symposium on Photochemistry (2016 IUPAC Photochem), IUPAC, 大阪府, http://web.apollon.nta.co.jp/iupac2016/, 生物発光体の分子構造に基づく蛍光色素開発について成果発表を行った。, International conference
05 Apr. 2016

Characterization of the luciferase active site for the color modulation mechanism in firefly bioluminescence
T. Hirano
Invited oral presentation, English, The 2015 International Chemical Congress of Pacific Basin Societies (Pacifichem 2015) BIOL: Luciferin/Luciferase Engineering (#410), Abstract, BIOL 253, Invited, Pacific Basin Societies of Chemistry, Hawaii, USA, http://www.pacifichem.org/, ホタル生物発光の波長制御を行う酵素機能に関する成果発表を行った。, International conference
16 Dec. 2015

Excited singlet states of firefly light-emitter analogs in luciferase supramolecular environments
T. Hirano
Invited oral presentation, English, The 2015 International Chemical Congress of Pacific Basin Societies (Pacifichem 2015), ORGN: Molecular and Supramolecular Photochemistry (#71), Abstract, ORGN 117, Invited, Pacific Basin Societies of Chemistry, Hawaii, USA, http://www.pacifichem.org/, ホタル生物発光の波長制御機構の光化学的知見に関する成果発表を行った。, International conference
15 Dec. 2015

ホタル生物発光の化学：基礎と応用の最前線
平野 誉
Invited oral presentation, Japanese, 平成27年度TIMS研究交流会, Invited, 筑波大学, つくば市, http://www.tims.tsukuba.ac.jp/index_j.html, 先端材料研究に関するシンポジウムで、生物発光材料の先端研究について、自身の成果も盛り込みながら解説した。, Domestic conference
24 Jul. 2015

ホタル生物発光の化学：基礎と応用の最前線
平野 誉
Invited oral presentation, Japanese, 平成27年度TIMS研究交流会, Invited, 筑波大学, つくば市, 先端材料研究に関するシンポジウムで、生物発光材料の先端研究について、自身の成果も盛り込みながら解説した。, Domestic conference
24 Jul. 2015

Color modulation mechanism of firefly (beetle) bioluminescence: an organic photochemistry approach with a substituent effect
T. Hirano
Invited oral presentation, English, 2nd DYCE-ASIA Workshop/ISSP International Workshop on “Life Science and Photonics”, Abstract, pp. 23−24, Invited, 東京大学, 柏市, 生物発光の最新データについて議論する本ワークショップで、ホタル発光の発光色制御機構に関する最新の成果発表を行った。, International conference
18 Dec. 2013

A Photochemical Aspect of Color Modulation Mechanism of Firefly (Beetle) Bioluminescence
Takashi Hirano
Invited oral presentation, English, The 5th Asia and Oceania Conference for Photobiology, The Japanese Photochemistry Association, Nara, Japan, International conference
Aug. 2011

ウミホタルルシフェリンアナログの化学発光特性制御
平野 誉
Invited oral presentation, Japanese, 第７回バイオオプティクス研究会理研シンポジウム「蛍光相関分光と情報伝達（７）」合同シンポジウムプログラム, バイオオプティクス研究会
Dec. 2010

発光分析のための生物発光色制御：ホタルの基本原理
平野 誉
Invited oral presentation, Japanese, 第６回バイオオプティクス研究会講演会, バイオオプティクス研究会
Dec. 2009

ホタルの仲間の生物発光色制御メカニズム
平野 誉
Invited oral presentation, Japanese, 第26回学術講演会抄録集（電気通信大学）, p. 12-13, 生物発光化学発光研究会
Jun. 2009

生物発光に学ぶ化学発光の高性能化
平野 誉
Invited oral presentation, Japanese, 第５回バイオオプティクス研究会講演会, バイオオプティクス研究会
Dec. 2008

Reaction mechanism of the imidazopyrazinone-bioluminescent system
Takashi Hirano
Invited oral presentation, English, 2007 Korea-Japan Symposium on Frontier Photoscience (2007-KJFP), Korean Society of Photoscience & The Japanese Photochemistry Association, Gyeongju, Korea, International conference
Nov. 2007

Electron-transfer oxygenation mechanism in the imidazopyrazinone bioluminescence
Takashi Hirano
Invited oral presentation, English, 2nd International Symposium on Organic Electron Transfer Chemistry (ISOETC-2007), Organizing Committee of ISOETC-2007, Yokohakma, JAPAN, International conference
Jan. 2007

生物発光の分子機構：ウミホタルの高性能発光について
平野 誉
Invited oral presentation, Japanese, 第３回バイオオプティクス研究会―バイオとオプティクスの融合―講演会, バイオオプティクス研究会
Oct. 2006

生物発光の分子メカニズムと発光分子素子の設計指針
平野 誉
Others, Japanese, 千葉大学化学セミナー, 千葉大学工学部共生応用化学科
Mar. 2006

生物発光に学ぶ色素センサー分子の開発
平野 誉
Invited oral presentation, Japanese, 第２回バイオオプティクス研究会―バイオとオプティクスの融合―講演会, バイオオプティクス研究会
Oct. 2005

生物発光の分子メカニズムと発光分子素子の設計指針
平野 誉
Public symposium, Japanese, 第7回分子ダイナミック分光ワークショップ, 光科学技術研究振興財団 第7回分子ダイナミック分光ワークショップ講演要旨集, 浜松
Jul. 2005

Development of the Chemistry of the Imidazopyrazinone-bioluminescence System: From the Bio- and chemiluminescence Mechanism to a Design of Sensor Molecules
T. Hirano; S. Nakai; T. Sekiguchi; S. Fujio; S. Maki; H. Niwa
Invited oral presentation, English, 13th International Symposium on Bioluminescence and Chemiluminescence, The International Society for Bioluminescence and Chemiluminescence, Yokohama, International conference
Aug. 2004

生物発光に学ぶ発光分子素子の設計指針
平野 誉
Invited oral presentation, Japanese, 第１回バイオオプティクス研究会―バイオとオプティクスの融合―講演会, バイオオプティクス研究会
Sep. 2003

工業的触媒反応を指向した高選択性パラジウム材料の開発
牧昌次郎; 松井 良; 原田靖裕; 平野 誉; 丹羽 治樹
Oral presentation, Japanese, 第42回有機合成化学関東支部新潟（長岡）シンポジウム（新潟）会（東京）,講演予稿集，(2001.11.23)
Nov. 2001

ギンコライドＢの全合成研究
小櫃和義; 牧井利通; 橋爪良信; 牧 昌次郎; 平野 誉; 丹羽治樹
Oral presentation, Japanese, 第43回天然有機化合物討論会（大阪）,講要旨集，2001.10.2～4)
Oct. 2001

フェニル置換イミダゾピラジノン誘導体のソルバトクロミズム
藤尾俊介; 牧 昌次郎; 丹羽治樹; 平野 誉
Oral presentation, Japanese, 2001年光化学討論会（金沢）,講演予稿集，(2001.9.10)
Sep. 2001

イミダゾピラジノン誘導体の金属イオン認識特性
関口卓志; 牧 昌次郎; 丹羽治樹; 平野 誉
Oral presentation, Japanese, 2001年光化学討論会（金沢）,講演予稿集，(2001.9.10)
Sep. 2001

ギンコライドＢの全合成研究
牧井利通; 小櫃和義; 橋爪良信; 牧 昌次郎; 平野 誉; 丹羽治樹
Oral presentation, Japanese, 日本化学会第80秋季年会（千葉）,講演予稿集，(2001.9.20～22)
Sep. 2001

工業的触媒反応を指向した高選択性パラジウム材料の開発
牧 昌次郎; 大川万季子; 松井 良; 原田靖裕; 平野 誉; 丹羽 治樹
Oral presentation, Japanese, 2001年電気化学秋季大会（東京）,講演予稿集，(2001.9.20～22)
Sep. 2001

Development of Hydrogenolysis-free Hydrogenation Selective Pd black Catalyst Deposited on Pd Sheet
Shojiro Maki; Makiko Okawa; Ryo Matsui; Takashi Hirano; Haruki Niwa
English, International Symposium on Integrated Synthesis 2001 (ISIS-2001) (Kyoto, Japan), Abstract, 25-26
Jun. 2001
19 Jun. 2001- 20 Jun. 2001

ラチア生物発光の分子機構; 発光反応生成物の構造解析
松井 良; 林 明生; 中井俊一郎; 小島 哲; 近江谷克裕; 伊藤喜之; 大橋陽子; 牧昌次郎; 平野 誉; 丹羽治樹
Oral presentation, 生物発光・化学発光研究会 第20回学術講演会：抄録集，(2001.6.9)
Jun. 2001

電極反応を用いたスチリルオレフィン選択的酸化開裂反応
牧 昌次郎; 平野 誉; 丹羽 治樹
Oral presentation, Japanese, 第25回エレクトロオーガニックケミストリー討論会（京都市）講演予稿集，(2001.6.18/19)
Jun. 2001

ＦＡＤおよび,ＦＭＮおよびリボフラビンのＭＡＬＤＩ,ＦＡＢおよびＥＳＩスペクトル：生体における酸化還元との類似性
伊藤善之; 林 明生; 吉原淳郎; 大橋陽子; 渋江俊道; 平野 誉; 牧 昌次郎; 丹羽治樹
Oral presentation, Japanese, 第49回質量分析総合討論会（東京）,講演要旨集，(2001.6.27)
Jun. 2001

Mass Spectrometric Characterization of FAD, FMN and Riboflavin: Analogy to the Biological Redox Reaction
Yoshiyuki Ito; Yoko Ohashi; Akio Hayashi; Toshimichi Shibue; Shojiro Maki; Takashi Hirano; Haruki Niwa
English, The 49th ASMS Conference on Mass Spectrometry and Allied Topics (Chicago, IL); Abstract
May 2001
27 May 2001- 31 May 2001

ラチアルシフェラーゼの生成とその性質
小島 哲; 鈴木智恵; 牧 昌次郎; 平野 誉; 丹羽治樹; 近江谷克裕
Oral presentation, Japanese, 日本化学会第79春季年会（兵庫,神戸）,講演予稿集ＩＩ，(2001.3.28)
Mar. 2001

マススペクトロメトリーにおけるＦＡＤおよび関連化合物の２段階１電子還元反応
伊藤善之; 林 明生; 吉原淳郎; 大橋陽子; 平野 誉; 牧 昌次郎; 丹羽治樹
Oral presentation, Japanese, 日本化学会第79春季年会（兵庫,神戸）,講演予稿集ＩＩ，(2001.3,28)
Mar. 2001

エクオリン生物発光におけるエミッターの構造決定：セレンテラミドフェノレートアニオンの蛍光特性
今井祐子; 平野 誉; 牧 昌次郎; 丹羽治樹; 大橋 守
Oral presentation, Japanese, 日本化学会第79春季年会（兵庫,神戸）,講演予稿集ＩＩ，(2001.3.28)
Mar. 2001

ギンコライドＢの全合成研究
小櫃和義; 牧井利通; 牧 昌次郎; 平野 誉; 丹羽治樹
Oral presentation, Japanese, 日本化学会第79春季年会（兵庫,神戸）,講演予稿集ＩＩ，(2001.3.28)
Mar. 2001

水素添加反応を選択的に行うパラジウム触媒の開発
大川万季子; 松井 良; 原田靖裕; 牧 昌次郎; 平野 誉; 丹羽治樹
Oral presentation, Japanese, 日本化学会第79春季年会（兵庫,神戸）,予稿集ＩＩ，(2001.3.30)
Mar. 2001

パラジウム触媒を用いた，選択的水素添加反応の開発
大川万季子; 松井 良; 原田靖裕; 牧 昌次郎; 平野 誉; 丹羽治樹; 小泉 恵; 錦 善則; 井上博史; 岩倉千秋
Oral presentation, 第20回メディシナルケミストリーシンポジウム／第９回日本薬学会医薬化学部会年回（調布，東京），講演予稿集
Dec. 2000

ラチア生物発光の分子基盤
小島 哲; 鍋谷卓司; 伊藤喜之; 牧 昌次郎; 平野 誉; 丹羽治樹; 鈴木知恵; 近江谷克裕; 絹見朋也
Oral presentation, 第42回天然有機化合物討論会（宜野湾，沖縄），講演要旨集
Nov. 2000

発光貝ラチアルシフェラーゼの精製と活性発現について：第73回日本生化学大会（横浜）
小島 哲; 鈴木知恵; 鍋谷卓司; 牧 昌次郎; 平野 誉; 丹羽治樹; 近江谷克裕
Oral presentation, Japanese, 生化学
Oct. 2000

エクオリン生物発光におけるエミッターの蛍光特性
今井裕子; 平野 誉; 牧 昌次郎; 丹羽治樹; 大橋 守
Oral presentation, Japanese, 2000年光化学討論会（札幌），講演予稿集Ⅱ
Sep. 2000

新しいソルバトクロミズム色素：２-フェニルイミダゾピラジノン誘導体の吸収・蛍光特性
中井俊一郎; 平野 誉; 牧 昌次郎; 丹羽治樹
Oral presentation, Japanese, 2000年光化学討論会（札幌），講演予稿集Ⅱ
Sep. 2000

発光巻き貝ラチア生物発光の分子基盤研究
丹羽治樹; 小島 哲; 牧 昌次郎; 平野 誉; 近江谷克裕
Public symposium, Japanese, 文部省科学研究費補助金 特定研究（Ａ）「未解明生物現象を司る鍵化学物質」第一回公開シンポジウム
Sep. 2000

光照射下電極反応を用いたイソイタリセンの合成
原田靖裕; 牧 昌次郎; 丹羽治樹; 平野 誉; 山村庄亮
Oral presentation, Japanese, 第24回エレクトロオーガニックケミストリー討論会（埼玉，岡部），講演予稿集 Ⅱ
Jun. 2000

電解によるアルケン類の選択的水素添加反応の開発
松井 良; 牧 昌次郎; 平野 誉; 丹羽治樹; 吉田秦樹; 尾形節郎; 中松秀司; 井上博史; 岩倉千秋
Oral presentation, Japanese, 日本化学会第78春季年会（千葉，船橋），講演予稿集Ⅱ
Mar. 2000

ギンコライドＢの全合成研究
小櫃和義; 牧 昌次郎; 平野 誉; 丹羽治樹
Oral presentation, Japanese, 日本化学会第78春季年会（千葉，船橋），講演予稿集Ⅱ
Mar. 2000

ラチア発光系におけるルシフェラーゼの構造と発光活性
小島 哲; 鍋谷卓司; 牧 昌次郎; 平野 誉; 丹羽治樹; 近江谷克裕
Oral presentation, Japanese, 日本化学会第78春季年会（千葉，船橋），講演予稿集Ⅱ
Mar. 2000

マススペクトロメトリーによるラチアルシフェラーゼの構造解析
鍋谷卓司; 伊藤善之; 小島 哲; 近江谷克裕; 絹見朋也; 黒野 定; 牧 昌次郎; 平野 誉; 丹羽治樹
Oral presentation, Japanese, 日本化学会第78春季年会（千葉，船橋），講演予稿集Ⅱ
Mar. 2000

エクオリン生物発光におけるエミッターの蛍光特性
今井祐子; 平野 誉; 牧 昌次郎; 丹羽治樹; 大橋 守
Oral presentation, Japanese, 日本化学会第78春季年会（千葉，船橋），講演予稿集Ⅱ
Mar. 2000

化学発光性を有するイミダゾピラジノン誘導体の基本物性
平野 誉; 丹羽治樹; 橋爪大輔; 安井正憲; 岩崎不二子
Oral presentation, Japanese, 日本化学会第78春季年会（千葉，船橋）講演予稿集Ⅱ
Mar. 2000

Supramolecular Interaction in Aequorin Bioluminescence
Takashi Hirano; Yuko Imai; Takuya Shibata; Hakruki Niwa; Yoshihiro Ohmiya; Mamoru Ohashi
Public symposium, Japanese, Information Exchange Seminor, Photoconversion and Photosynthesis: Past, Present and Future Prospects（Under US-Japan Coorporative Project）（Okazaki, Japan），Abstracts
Nov. 1999

エクオリン生物発光における超分子化学：分子認識特性
平野 誉; 芝田拓也; 橋爪大輔; 安井正憲; 近江谷克裕; 牧 昌次郎; 丹羽治樹; 岩崎不二子; 大橋 守
Oral presentation, Japanese, 1999年光化学討論会（岡山），講演要旨集
Sep. 1999

光誘起電子移動反応を用いたヘテロ環化合物の合成
石井英樹; 今井祐子; 牧 昌次郎; 平野 誉; 丹羽治樹; 大橋 守
Oral presentation, Japanese, 1999年光化学討論会（岡山），講演要旨集
Sep. 1999

ラチア生物発光におけるルシフェリンの構造活性相関
小島 哲; 牧 昌次郎; 平野 誉; 丹羽治樹; 近江谷克裕
Oral presentation, Japanese, 生物発光化学発光研究会第18回学術講演会（東京，品川），講演予稿集
May 1999

ラチア発光系に関与する蛍光性蛋白質の構造
小島 哲; 牧 昌次郎; 平野 誉; 丹羽治樹; 近江谷克裕
Oral presentation, Japanese, 日本化学会第76春季大会（神奈川，横浜），講演予稿集Ⅱ
Mar. 1999

ピクロトキシン誘導体の調製
小櫃和義; 牧 昌次郎; 平野 誉; 丹羽治樹
Oral presentation, Japanese, 日本化学会第76春季大会（神奈川，横浜），講演予稿集Ⅱ
Mar. 1999

光照射下電極反応を用いたイタリセンの合成
原田靖裕; 牧 昌次郎; 丹羽治樹; 平野 誉; 山本庄亮
Oral presentation, Japanese, 日本化学会第76春季大会（神奈川，横浜），講演予稿集Ⅱ
Mar. 1999

ジメチルグロイオシフォンAの合成
橋爪良信; 牧 昌次郎; 平野 誉; 丹羽治樹; 大橋 守
Oral presentation, Japanese, 日本化学会第76春季大会（神奈川，横浜），講演予稿集Ⅱ
Mar. 1999

光誘起電子移動反応を用いた多環性化合物の合成
今井祐子; 石井英樹; 牧 昌次郎; 平野 誉; 丹羽治樹; 大橋 守
Oral presentation, Japanese, 日本化学会第76春季大会（神奈川，横浜），講演予稿集Ⅱ
Mar. 1999

光誘起電子移動反応を用いたヘテロ環性化合物の合成
石井英樹; 今井祐子; 牧 昌次郎; 平野 誉; 丹羽治樹; 大橋 守
Oral presentation, Japanese, 日本化学会第76春季大会（神奈川，横浜），講演予稿集Ⅱ
Mar. 1999

Practical advanced instrumental analysis
Oct. 2021 - Present
The University of Electro-Communications

Chemistry and Biotechnology Laboratory II
Oct. 2018 - Present
The University of Electro-Communications

Polymer and Organic Chemistry
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The University of Electro-Communications

Instrumental Analysis
Apr. 2018 - Present
The University of Electro-Communications

Fundamental of Engineering Science
Apr. 2016 - Present
The University of Electro-Communications

Principles of Chemistry I
Apr. 2016 - Present
The University of Electro-Communications

Seminar A
Apr. 2011 - Present
The University of Electro-Communications

Fundamentals of Photochemistry
Oct. 2010 - Present
The University of Electro-Communications

Chemistry Laboratory
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The University of Electro-Communications

General Chemistry
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The University of Electro-Communications

Comprehensive Communications Sciences
Apr. 2012 - Jan. 2022
The University of Electro-Communications

2021先端科学技術総論
Sep. 2021 - Oct. 2021
新潟大学大学院自然科学研究科

Global Liberal Arts Program
Oct. 2016 - Mar. 2019
Tokyo University of Foreign Studies

Chemical biology
Sep. 2018 - Sep. 2018
Nihon University

Polymer Science
Apr. 2013 - Mar. 2018
The University of Electro-Communications

Topics in Chemistry III
Dec. 2017 - Dec. 2017
Okayama University of Science

Organic Chemistry
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The University of Electro-Communications

Bioscience and Technology Laboratory Ⅱ
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The University of Electro-Communications

物質・生命理工学特別講義 生物発光化学特論
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Gunma University

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The University of Electro-Communications

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The University of Electro-Communications

Transport Phenomena
Oct. 2014 - Mar. 2015
The University of Electro-Communications

キャリア教育演習
Apr. 2014 - Sep. 2014
The University of Electro-Communications

Polymer Science
Apr. 2012 - Sep. 2012
The University of Electro-Communications

Organic Chemistry II
Apr. 2011 - Sep. 2012
Tokyo University of Agriculture and Technology

Materials and Bioinformatics Engineering Laboratory B
Oct. 2003 - Mar. 2012
The University of Electro-Communications

Fundamentals and Topics of Analytical Chemistry
Oct. 2000 - Mar. 2010
The University of Electro-Communications

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Apr. 2004 - Sep. 2009
The University of Electro-Communications

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Apr. 1996 - Sep. 2003
The University of Electro-Communications

Chemistry Laboratory
Oct. 1997 - Mar. 2003
The University of Electro-Communications

電子材料工学実験I&II
Apr. 1991 - Mar. 2003
The University of Electro-Communications

The electrochemical Society of Japan

生物発光化学発光研究会

The Society of Physical Organic Chemistry, Japan

American Society of Photobiology

American Chemical Society

The Society of Synthetic Organic Chemistry, Japan

Japanese Photochemistry Association

Chemical Society of Japan

Synthesis and Development of Chemiluminescent Soft Crystals for Spatiotemporal Control of the Stimulus-responsive Functions
Hirano Takashi
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area), ソフトクリスタル化学発光系の創製と学理探求を目指す, 17H06371
30 Jun. 2017 - 31 Mar. 2022

生物発光における鍵反応過程の分子機構と高性能化要因の解明
ホタルとウミホタルの生物発光の反応機構を司る鍵反応過程の機構解明を目指す。
01 Apr. 2018 - 31 Mar. 2021

Innovation of artificial Luminescence System by Modeling Firefly Bioluminescence
MAKI Shojiro; NIWA Haruki; HIRANO Takashi; KOJIMA Satoshi
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research (C), 1. Confirmation of "rate-determining step" of luciferase. Luciferase has 2 functions are adenylylation site and oxygenation site. It is confirmed the adenylylation reaction is rate-determining step by analyzing adenylyl luciferin reaction. 2. Reaction analysis of adenylylation site. The adenylylation function is divided recognition step and reaction step. The adenylyl luciferin makes flash emission, though the emission intensity is enhanced, remarkably. This problem has been solved. I. On adenylylation function, structural recognition is dominant over chiral recognition. II. To be modified thiazoline site bulky, emission activity remarkably deterioration. III. An adenylylation of luciferin analogues makes emission activity enhance. IV. An addition of Pyrophosphate makes emission intensity flat. 3. Development of RGB emission (450, 560, 680nm) luciferin analogues. Firefly luciferin analogues have been designed and synthesized for making RGB emission color, based on the data of structure activity analysis. It is achieved by similarity three analogues in the first time of the world. 4. Discovery of lead for emission color changing method. It is longed for a signpost for emission color changing. From the data of structure activity analysis, the lead of emission color changing method is discovered. We are accomplishing to establish a hypothesis., 18510181
2006 - 2007

ヤコウタケ生物発光機構解明と標識材料の開発研究
牧 昌次郎; 丹羽 治樹; 平野 誉
日本学術振興会, 科学研究費助成事業, 電気通信大学, 萌芽研究, 初年度の研究により、「ヤコウタケ生物発光は酸素要求性」であることを確認した。すなわちヤコウタケ数個を縦に吊るし、系に不活性ガスを満たすと発光を一旦停止する。次いで不活性ガスを徐々に空気と置換すると、空気に触れた順に発光を再開した。一方、凍結乾燥したヤコウタケ(発光活性は消失)に水を添加すると、再び生物発光と同じ約525nmの蛍光を発することも判明した。これらからヤコウタケ生物発光には、「酸素と水」が必要であることが確認された。またヤコウタケ凍結乾燥体を粉末状にし、不活性ガス中で保存すれば「発光材料」として活用できることがわかった。 ヤコウタケの発光形態は不明であるが、月夜茸はルシフェリンールシフェラーゼ反応(L-L反応)により発光するとの報告がある。これを参考に、ヤコウタケの生物発光もL-L反応であると仮定し、ヤコウタケ発光物質の単離・抽出を試みることとした。 他の発光生物と同様にヤコウタケ子実体を破砕し、各種緩衝溶液等で発光関連タンパク(酵素)の抽出を試みたが、タンパクの可溶化には至らなかった。ところが本実験の過程で、沈殿物である破砕断片に発光が確認された。そこで、ヤコウタケ子実体の細胞壁を酵素消化によって除去・プロトプラスト化した後、酵素タンパクの可溶化を試みた。各種実験条件を詳細に検討したところ、酵素消化条件での加熱(約50度)により、ヤコウタケの発光活性が消失することが確認された。また界面活性剤による可溶化も試みた。市販のDetergent Test Kitを用いたところ、数種の界面活性剤で、ヤコウタケ子実体タンパクの可溶化に成功した。 現在、低温での酵素消化によるプロトプラスト化とタンパク可溶化、および界面活性剤による可溶化物からの発光関連物質の抽出を行っている。またメタノール等による発光基質(低分子有機化合物を想定)も並行して行っている。, 16655067
2004 - 2005

Investigation of Unutilized Bioluminescent Systems and Fluorescent Proteins, and Development of New Molecular Proves.
NIWA Haruki; HIRANO Takashi; MAKI Shojiro; OHMIYA Yoshihiro
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research (B), 1)From the marine luminescent worm, Odontosyll is phosphorea collected off from Mission Bay, San Diego, U.S.A., the light producing substance, Odontosyll is luciferin was isolated under the guidance of luciferin-luciferase reaction. The bioluminescence spectrum (λmax 500nm) using the isolated luciferin and the crude luciferase was similar to that of live specimens. The UV spectrum was essentially identical with that reported previously by Shimomura. The molecular formula of the luciferin was determined from the high resolution ESI mass spectrum to be C_<15>H_8O_<12>S_3. 2)Exploration of luminescent marine organisms was performed at New Caledonia, some luminous worm and sea hare was found. 3)From the fresh-water limpet like snail, Latia neritoides collected at the Nugtunu stream near Mt. Pirongia, New Zealand, the luciferase was isolated under the guidance of luciferin-luciferase reaction. The detailed biochemical studies indicated that the active form of the luciferase was found to be a hexamer of N-linked glycoprotein monomer having the molecular mass 31kDa. The cloning of the luciferase gene was succeeded. However heterologous expression of the gene was not succeeded so far., 15404009
2003 - 2005

Development of Conceputually New Photonics Materials Based on New Luciferins
NIWA Haruki; HIRANO Takashi; MAKI Shojiro
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research (C), Molecular basis of light emitting system of various bioluminescent organisms were investigated. The bioluminescence system of the marine sea fire worm Odontosyllis undecimdonta was found to exhibit typical luciferin-luciferase reaction. The luciferin was found to be able to extract with methanol, and the luciferase with hot water. The emition of bluewish green light was observed by mixing the methanol extract and the water extract. The isolation of luciferin from the methanol extract was attempted by using HPLC, and we found that the luciferin to be acidic substance(s) with high polarity. Owing to low quantity of the luciferin content, we could not determine the chemical structure so far. The bioluminescence system of the sea hare Plocamopherus imperialis was found also o exhibited luciferin-luciferase reaction. The sample was found to keep the bioluminescence ability even after storing at low temperature (below-80℃) for years. In connection of exploration of bioluminescence system of the mushroom Mycea chlorophos, we isolated basidiospores from the fruit-body of the mushroom collected from Hatijuo Island. The basidospores were germinated, from which a single strain of the fruiting mycelium was isolated. Using the single strain of the fruiting mycelium, we succeeded laboratory cultivation of fruiting body. We attempted the isolation of fluorescent substance(s) with the maximum around green light(510nm), resulting to the identification of lumichrom. In the course of the construction of Bioluminescence Resonance Energy Transfer (BRET) system utilizing the firefly bioluminescence system coupled with Aequorea green fluorescence protein (GFP), the molecular design of blue light-producing firefly luciferin analogs was performed. After brief studies on the structure-bioluminescence activity relation ship, we succeeded the synthesis of an analog having a bioluminescence maximum shorter than that of native firefly luciferin. In connection with the development of new photonics materials based on bioluminescence systems, we succeeded new imidazopilazinone derivatives with extended π-systems., 14580608
2002 - 2003

Study on Molecular Mechanism of Latia Biohminescnece
HARUKI Niwa; MAKI Shojiro; HIRANO Takashi
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-communications, Grant-in-Aid for Scientific Research on Priority Areas, (1) Studies on substrate specificity using a series of analogs of the Latia luciferin suggested that the Latia luciferase recognized strrctly the 2,6,6-trimethylcyclohexene ring moiety in the luciferin structure. The corresponding enol acetate and benzoate analogs also possessed luciferin activities, indicating the formate moiety to be not essential for the Latia bioluminescence reaction. The rate of light production was delayed when the enol acetate analogue and benzoate analogue were used, indicating the hydrolysis step of the enol ester moiety at the active site of the luciferase may be rate determining step of the light production reaction. Interestingly, the corresponding 2,6-dimethylphenyl analogue also have luciferin activity Further studieson the relationship between structure and luciferin activity are currently under investigation. (2) Purification of Latia luciferase was achieved by a 5-step procedure including affinity chromatography on a Con A-supported column. (3 ) The purified luciferase exhibited a luciferin/luciferase reaction with the Latia luciferin without any cofactors such as "purple protein," previously reported as the cofactor, and gave the sarne bioluminescence spectra as those obtained with the crude luciferase containing "purple protein," indicating that the light emitter of Latia bioluminescence is a fluorophore present in the luciferase molecule. (4) The bioluminescent-active luciferase was found to have a molecular mass of 180 kDa and to be present as a hexamer of bioluminescent-inactive monomers having a molecular mass of 31 kDa. The Latia luciferase was found to be a glycoprotein. The glycoside moiety may be important for keeping the oligomeric structure and/or for bioluminescence reaction. (5) The c-DNA for Latia luciferase was cloned. The primary structure, deduced from the nucleotide sequence, consists of 294 amino acid residue in a single peptide chain with an N-glycosylated NSS sequence., 12045226
2000 - 2002

Development of Fluorescent ON/OFF Mode Biosensor Based on GFP Chromophore
NIWA Haruki; MAKI Shojiro; HIRANO Takashi
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-communications, Grant-in-Aid for Scientific Research (C), 1) In connection with the development of new fluorescent biosensor based on GFP fluorescent chromophore several lead compounds with a 4-arylmethylidene-5-imidazolone structure were prepared and their fluorescence properties were investigated. Starting with 2-naphthalenecarboxaldehyde, 6-methoxy-2-naphthalenecarboxaldehyde, 4-(dimethylamino)benzaldehyde, and 1-pyrenecarboxaldehyde, we could prepare 1,2-dimethyl-4-(2-naphthylmethylidene)-5-imidazolone, 1,2-dimetnyl-4-(6-methoxy-2- naphthylmethylidene)-5-imidazolone, 1,2-dimethyl-4-[4-(dimethylamino)phenylmethylidene]-5-imidazolone, and 1,2-dimethyl-4-(1-pyrenylmethylidene)-5-imidazolone by utilizing Erlenmeyer ablactate method. We found that all compounds prepared exhibited very weak fluorescent properties in solution state, whereas they showed 2000〜3000 times strong fluorescence in ethanol glass matrices at 77 ° K. Fluorescence maximums were 520 nm for the 2-naphthyl derivative, 460nm for the 6-methoxy-2-naphthyl derivative, 520 nm for the 4-(dimethylamino)phenyl derivative, and 503 nm for the 1-pyrenyl derivative. 2) We attempted to prepare the 4-aryliden-5-imidazolone derivative having metal-chelating functional groups and we could obtained 1-methyl-4-[ (3-bromophenyl)methylidene]-2-(3-bromophenyl)-5-imidazolone, being able to introduce chelating groups. Reaction of the imidazolone derivatives with morpholine in the presence of a Pd(0) catalyst afforded the corresponding morpholino derivative. Introduction of a Ca-chelating functional group is under investigation. 3) For studying fluorescence properties of the GFP chromophore, we investigated the relationship between fluorescence life times and solvent viscosities by using a GFP chromophore model imidazolone derivative. As results, the fluorescence lifetime of the GFP chromophore was prolonged with increasing the viscosity of the solvent used., 12680588
2000 - 2001

Development of Selective Alkene Hydrogenation with Atomic Hydrogen Permeating through a Pd Sheet Electrode for Industrialization
MAKI Shojiro; HIRANO Takashi; NIWA Haruki
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research (C), Hydrogenation of an alkene is quite important for organic' syntheses employing a catalyst (Pd, Ni, Pt) which chemisorbes active hydrogen, however, hydrogenolysis of allylic C-O bonds and benzyloxy groups (Bn-O-) also takes place under the same conditions. Therefore, it is difficult for alkenes having an allyloxy and/or benzyloxy group to be hydrogenated by active hydrogen without the hydrogenolysis. A new hydrogenation system utilizing electrochemically produced activehydrogen has been successful in the saturation of several unsaturated organic compounds such as styrene and its derivates. The reaction cell is made up of two compartments separated by a Pd sheet as cathode, where galvanostatic electrolysis of water is carried out to produce the active hydrogen atone side of the Pd sheet, and a substrate is hydrogenated at the opposite side surface by active hydrogen permeating through the Pd sheet., 12650848
2000 - 2001

Studies on a luminescent reaction mechanism of ion-sensing bio-and chemiluminescence systems
HIRANO Takashi
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research (C), This research project aims to establish the bioluminescence mechanism of the photoprotein aequorin(AQ)which has a calcium-ion sensing, efficient luminescence, and color-regulation properties, and to make a fundamental theory for molecular design of desirable chemiluminescent molecules. Structure elucidation of coelenteramide during AQ bioluminescence is an important problem in the bioluminescence mechanism. To clarify this problem, the fluorescent properties of the phenolate anions of coelenteramide analogues were investigated. Fluorescence of phenolate anion in non-polar solvents was observed by electronic excitation of a hydrogen-bonded complex of a coelenteramide analogue with a hydrogen-bond donor molecule. In polar solvents, phenolate anion was directly generated by using a base, and its fluorescence was studied. The se results confirm that the singlet-excited stated of phenolate anion of coelenteramide has an intramolecular CT character. The fluoro substituent effect on the fluorescent property of phenolate anions was also clarified and explained the bioluminescent pr operty of the fluorinated semi-synthetic AQ.These results consistenly support the assignment that phenolate anion is the ionic structure of the excited light-emitter in BFP during AQ bioluminescence. To establish the molecular mechanism of the lumi nescence reaction of the substrate(an imidazopyrazinone derivative)of AQ bioluminescence, we have investigated fundamental physical properties of imidazopyrazinone derivatives and their electron transfer reactivity, and found an inter molecular addition reactivity with electron-acceptor molecules. We also found that an imidazopyrazinone derivative acted as a ligand for making metal complexes. To confirm these new findings, detailed studies on the physical property and reactivity of imidazopyrazinone derivatives are in progress., 11640578
1999 - 2000

Molecular Bases on Bioluminescence and Luminous Behavior Professor
NIWA Haruki; OHMIYA Yoshihiro; MAKI Shojiro; HIRANO Takashi; OHBA Nobuyosi
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-communications, Grant-in-Aid for international Scientific Research, Molecular base on bioluminescence of fresh water limpet-like snails Latia neritoides in New Zealand was investigated. Rapid and convenient method for purification of the Latia luciferase was established. (1) The Latia luciferase was found to be an N-linked glycoprotein, and to exhibit bioluminescence activity without any cofactor. The size exclusion chromatography analysis coupled with SDS-PAGE analysis and MALDI-TOF mass spectrometry indicated that the bioluminescent active Latia luciferase is a homohexamer, whose molecular weight is ca. 180,000 and the molecular weight of the non-bioluminescent subunit protein is ca. 31,000. (2) Although the natural Latia luciferin has an enol formate group, the formyl one was found to be not essential functionality, but enol acetate has also bioluminescence activity, indicating that the bioluminescence system of Latia is completely different from bacteria's ones believed previously and that the Latia luciferase has also an esterase activity. The formation of enolate anion in the Latia luciferase may be essential initial event in the bioluminescence reaction. (3) The Latia m-RNA was extracted from live specimens, from which Latia c-DNA library was constructed. Now cloning of the luciferase c-DNA is in progress., 09041100
1997 - 1999

発光蛋白質エクオリン生物発光における超分子構造
大橋 守; 平野 誉
日本学術振興会, 科学研究費助成事業, 電気通信大学, 重点領域研究, オワンクラゲの生物発光は発光蛋白質エクオリンがカルシウムイオンにより刺激されて励起青色蛍光蛋白質(BFP)を生じ、ついで緑色蛍光蛋白質(GFP)にエネルギー移動して励起GFPを生じ、そこから発光極大510nmの緑黄色蛍光に由来するものといわれている。本研究では変性GFPやGFPを酵素分解して得たクロモペプチドが蛍光を示さないことから、生体内における蛍光量子収率が80%という高収率を理解するためにそのモデル化合物を合成し、蛍光挙動を比較検討した。合成したモデル化合物4-(4-hydroxyphenyl)methylideneimidazol-5-one(I)は溶液中では殆ど蛍光を示さないが77KでEtOH中剛体マトリクスでは470nm付近に強い蛍光を示した。同様に天然から得られたクロモペプチドもEtOH剛体マトリクス中で蛍光を示すようになり、その極大はモデル化合物(I)と一致した。(I)は光照射により側技のシス-トランス異性化をおこすことも明らかにした。このことはGFP中では分子内水素結合やクロモフォアの存在するキャビティのためにシス-トランス異性化が阻害されることにより高量子収率の蛍光を示すものと解釈しうることを示した。GFPは又亜ジチオン酸ナトリウムで還元すると蛍光を失い、空気酸化で再生することが知られている。モデル化合物(I)は亜ジチオン酸ナトリウムでジヒドロ化合物を与え、もはや蛍光を生じないが、このものは空気酸素存在下で再び(I)が再生されることを見出した。このことはGFPの生合成に対して重要な知見を与える結果である。, 08219212
1996 - 1996

イミダゾピラジン化学発光系における励起分子生成機構の解明と発光能の制御
平野 誉
日本学術振興会, 科学研究費助成事業, 電気通信大学, 奨励研究(A), イミダゾピラジン誘導体としてセレンテラジンアナログを選び、その発光機構と発光能の制御を行うために6位のフェニル基上に種々の置換基を導入したセレンラジンアナログとアダマンチルメチル基を有するアナログの化学発光特性を調べた。6-フェニル体の化学発光では、一重項励起分子生成効率が置換基の影響を受けないが、発光波長は大きく影響を受けることがわかった。特にジメチルアミノ置換体のジグリム中での化学発光は500nmまで長波長シフトした。この理由は、反応で生成する中性のセレンテラミドアナログの一重項励起状態が分子内電荷移動性を有するためであることが明らかになった。また、2位と8位のそれぞれにアダマンチルメチル基を有するアナログの化学発光では、非極性のアダマンチル基が発光反応で生成するアニオン性励起分子の安定性に影響し、プロトン化速度の変化による発光波長の変化が観測された。 2-フェニルイミダゾピラジン誘導体は長波長蛍光を示す。この特性を生かした発光物質を開発するために、2-フェニルイミダゾピラジノンの酸化的二量化生成物を合成した。この化合物はたいへん不安定であるが発光能を残し、しかもその発光波長は620nmまで長波長シフトしている。発光反応では二量体の一方のイミダゾピラジン環が酸素と反応して励起分子を生成し、この励起分子にはもう一方のイミダゾピラジン環が残っているために長波長発光を示したことがわかった。この特性を積極的に利用するために、ベンゼンに2つのイミダゾピラジン骨格を置換した誘導体を合成した。ジメチルスルホキシド中、塩基存在下で化学発光を行うと橙色発光が確認され、長波長発光を実現することに成功した。可視部での発光は生体内の活性酸素の定量への応用が期待されるため、さらに発光量子収率などの発光特性の確立を進めている。, 07740491
1995 - 1995

発光蛋白質エクオリン生物発光における超分子構造
大橋 守; 平野 誉; 丹羽 治樹
日本学術振興会, 科学研究費助成事業, 電気通信大学, 重点領域研究, 発光オワンクラゲの発光システムは励起分子を生成する蛋白質エクオリン(AQ)と,この励起エネルギーを受容して緑色蛍光を放出する緑色蛍光蛋白質(GFP)から構成されている。AQは発光基質セレンテラジン(CZ)とアポエクオリン(ApoAQ)と酸素分子の複合体であり,カルシウムイオンと結合して生物発光する。発光種はApoAQとセレンテラミドからなる超分子青色蛍光蛋白質(BFP)である。一方GFPは翻訳後修飾によりポリペプチド主鎖の3個のアミノ酸残基が発色団を形成しているといわれている。本研究ではAQ生物発光におけるAp-AQ-CZ間及びAQ-GFP間で構築される超分子構造と発光の分子過程との関係を明らかにすることを目的とした。得られた結果を以下に示す。 (1)フォトアフィニティラベル法によるAQ超分子構造の解明を目指し,光反応性を有するトリフルオロメチルアジリン基を持つCZアナログから半合成AQの合成に成功した。発光活性は天然型の1%であった。アジド基を有するCZアナログの合成にも成功している。 (2)GFPの発色団を決定するためWardらにより提唱されているイミダゾロン骨格を有する構造に対応するモデル化合物の合成に成功した。合成品はUV吸収が天然GFPの酵素分解で得られた色素成分と類似の挙動を示し,かつ蛍光特性を持ち,塩基性条件下では510nmに天然GFPの蛍光極大と一致する蛍光を示したので,この部分構造がGFPの発色団であることが証明された。 (3)アダマンタン基を有するCZアナログを合成し,生物発光特性の制御を試みた。発光極大は天然型より20nm程短波長で,発光強度は天然型の2倍に達した。, 07229216
1995 - 1995

イミダゾピラジン化学発光系の励起分子生成機構の解明
平野 誉
日本学術振興会, 科学研究費助成事業, 電気通信大学, 奨励研究(A), オワンクラゲやウミホタルの発光基質は共通骨格であるイミダゾピラジン骨格を有する。本研究ではイミダゾピラジン誘導体の化学発光反応における励起分子生成機構を明らかにするために、誘導体の物理科学的性質と化学発光能の相関を調べることを計画した。このため、まず6-フェニルイミダゾピラジン誘導体のフェニル基上のパラ位に系統的に置換基を導入した誘導体5種を合成した。この誘導体を用いて化学発光特性に及ぼす置換基効果を検討した。この結果、空気飽和条件下ジメチルスルホキシド中における化学発光の量子収率は置換基の種類に依存せず、0.1%付近の値をとり、蛍光量子収率と反応効率を考慮して算出した励起分子の生成効率は電子受容性置換基を有する方がわずかに上昇することがわかった。この結果は反応中間体に推測されているジオキセタノン中間体が分離して励起分子を生成する過程には置換基による電子的性質の変化があまり影響せず、生物発光にみられる高い発光量子収率を再現できないことを示している。置換基効果が顕著に現れる特性は発光後生成物の蛍光波長と蛍光量子収率である。特に発光後生成物の蛍光波長は電子供与性置換体ほど長波長シフトし、同時に蛍光量子収率が高くなることがわかった。また、ジメチルアミノ基置換体ではアニオン種よりも中性種の方が長波長部で蛍光を示す。この新しく見いだされた発光後生成物の特性を生かすためにジグリム中など他の条件下における化学発光の検討を続けている。 6-フェニルイミダゾピラジン誘導体の紫外可視吸収スペクトルとNMRを測定した結果、6位のフェニル基上の置換基効果が物理化学的性質に大きな影響を及ぼさないことがわかった。さらに酸素との反応に直接関与するアニオン種を安定に発生させる条件の検討を続けており、基本的物性データと化学発光特性との比較を行なう予定である。, 06854030
1994 - 1994

発光蛋白質エクオリンの生物発光における超分子構造のダイナミクス
大橋 守; 近江谷 克裕; 陳 鳳啓; 平野 誉
日本学術振興会, 科学研究費助成事業, 電気通信大学, 重点領域研究, オワンクラゲの発光蛋白質エクオリンはCa^<+2>イオンの存在下Blue Fluorescent Protein(BFP)の励状態を生じ460nmに発光する.エクオリンは発光基質セレンテラジンとアポエクオリン(189 アミノ酸残基から成るアポ蛋白質)及び分子状酸素から組立てられているが,その精緻な構造は明らかにされていない.本研究ではこの生物発光に関与する超分子構造のダイナミクスを解明するため以下の検討を行った. 1)この構造解明に関連してアポエクオリンの活性部位をフォトラベル法により解明することを計画し,光感作性基トリフルオロメチルジアジリン基を有するセレンテラジン及びセレンテラミドの合成に成功した.この光感作性セレンテラジンも天然型と同様にアポエクオリンに取り込まれ,生物発光を行うことを確認した.又トリフルオロメチルジアジリン基を持つセレンテラミドは光照射により溶媒中のメタノールと反応することを知った.今後はこの半合成エクオリンを大量に合成し,フォトラベルアポエクオリンの酵素分解,マススペクトロメトリーを組合わせて活性部位を特定する. 2)セレンテラジンは環境により多彩な発光を示す.例えば86番目のアミノ酸を変化させたAQW86Fは天然460nmの発光を400nmにシフトさせる.ただ一種のアミノ酸の変化により発光波長が変わることは精緻な超分子構造を予想させる.BFPはEDTA,DTT存在下アポエクオリンとセレンテラミドを共に培養すると再生される.この時N-メチルセレンテラミドを用いても同様な蛍光が観測されることより,従来アミドアニオンの励起状態からの発光とされてきた発光種の構造について,新しくフェノラートアニオンである可能性が生じた.従来の学説の再検討を要する結果となった.この点は更に確認実験を続けている., 06240221
1994 - 1994

Mass Spectrometric Approach to the Study of Biological Transducers
OHASHI Mamoru; SCHMITZ Francis j.; MATSUMOTO Hiroyuki; HIRANO Takashi; JACKSON Kenneth w.
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for international Scientific Research, The aim of this project is to elucidate the molecular processes associated with biological communication systems such as vision or bioluminescence by means of mass spectrometry in collaboration with prof.Ohashi's group of the University of Electro-Communications (UEC) and the research groups of Prof.Matsumoto of Biochemistry Dept., and Prof.Schmitz of Chemistry Dept.of Oklahoma University (OU). The mutual exchanges which have been done between the three groups are as follows ; In 1992, in Sep.Matsumoto visited UEC,in Oct.Tsujimoto visited OU.In 1993 from Jan.to May, Azegani, Graduate student of UEC,joined Schmitz's group to extract several cytotoxic compounds from marine sources, in Sep.Kinumi, Graduate student of UEC,joined Matsumoto's group to prepare oligopeptides related to Phosrestin, in Nov.Ohashi and Hirano visited OU to give a scminar. In 1994, Jakson (in Mar), Schmitz (in Jun.), Matsumoto (in Jul.) visited UEC,in Aug.Hirano and Niwa visited Scripps Institution of Oceanography, UCSD,OU and Friday Harbor of Washington Univ.to collect bioluminescent organism, in Nov.Kinumi temporally visited UEC to establish mass spectrometric methods for elucidating the post-translational modification of phosrestin. The UEC group has attempted to use mass spectrometry to elucidate the active center of aequorin bioluminescence, while the OU groups have mainly concerned elucidating the post-translational modification of Phosrestin, which is in fly photoreceptor cells undergoing light-induce reversible phosphorylation in vivo, and determining the in vivo phosphorylation site by mass spectrometry. The collaboration of the three groups have proceeded smoothly and the joint paper entitled "Phosphorylation and N-terminal acetylation of phosrestin 1 in fly eyes" by Kinumi, Jachson, Kubota, Ohashi, and Matsumoto will be presented at the 1995 ASMS meeting., 04045024
1992 - 1994

新規セレンテラジン誘導体
Patent right, 木山正啓, 牧 昌次郎, 平野 誉, 岩野 智, 宮脇敦史, 特願2018-60762, Date applied: 27 Mar. 2018, The University of Electro-Communications, 2018-165265, Date announced: 25 Oct. 2018, 特許第7036343, Date issued: 07 Mar. 2022, 海洋生物発光基質の長波長化技術

蛍光色素
Patent right, 平野 誉, 中川達規, 牧昌次郎, 丹羽治樹, 特願2011-108654, Date applied: 13 May 2011, 国立大学法人電気通信大学

ビスイミダゾピラジノン誘導体及びビスアミノピラジン誘導体並びに化学発光物質
Patent right, 平野 誉, 牧昌次郎, 丹羽治樹, 特願2004-067098, Date applied: 10 Mar. 2004, 三菱化学株式会社, 特許第4561132号, Date issued: 06 Aug. 2010

ビスイミダゾピラジノン誘導体及びビスアミノピラジン誘導体
Patent right, 平野 誉, 牧昌次郎, 丹羽治樹, 特願2003-195905, Date applied: 11 Jul. 2003, 三菱化学株式会社, 特許第4363098号, Date issued: 28 Aug. 2009

[アシルアミノピラジナト-Ｏ，Ｎ]ボロン誘導体及び蛍光色素
Patent right, 平野 誉, 牧昌次郎, 丹羽治樹, 特願2008-244890, Date applied: 24 Sep. 2008, 国立大学法人 電気通信大学

複素環化合物及び発光方法
Patent right, 牧昌次郎, 小島 哲, 丹羽治樹, 平野 誉, 特願2006-086175, Date applied: 27 Mar. 2006, The University of Electro-Communications

複素環化合物及び発光甲虫ルシフェラーゼ発光系用発光基質
Patent right, 丹羽治樹, 牧昌次郎, 平野 誉, 特願2005-031574, Date applied: 08 Feb. 2005, The University of Electro-Communications

芳香族有機化合物の分解方法
Patent right, 特願2003-116616, Date applied: 22 Apr. 2003