1992 Fiscal Year Final Research Report Summary
A Study of Electron-Transfer Pathways in the Electron-Transfer Reactions of Metal Complexes and Hemoproteins
| Project/Area Number |
03453049
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
無機・錯塩・放射化学
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| Research Institution | Nara Women's University |
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Principal Investigator |
TSUKAHARA Keiichi Nara Women's University Department of Chemistry Assistant Professor, 理学部, 助教授 (70112117)
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| Co-Investigator(Kenkyū-buntansha) |
KATO Masako Nara Women's University Department of Chemistry Research Associate, 理学部, 助手 (80214401)
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| Project Period (FY) |
1991 – 1992
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| Keywords | Electron-Transfer Reaction / Electron-Transfer Pathway / Hemoprotein / Chemically Modified Myoglobin / Zinc Myoglobin / Porphyrins / Photoinduced Electron-Transfer Reaction / Intramolecular Electron Transfer |
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| Research Abstract |
1) Role of the Heme Propionates in the Reduction of Metmyoglobin-It is suggested that the heme propionates have an important role in the reductions of metmyoglobins by using the dimethylester hemins and octaethylhemin which has no propionates in the heme.
2) Redox Behavior of Viologen Attached Metmyoglobin-Metmyoglobin whose lysine residue was modified with viologen was newly prepared and reduced by dithionite ions faster than native metmyoglobin. It is suggested that the viologen attached to myoglobin is reduced, following the rapid intramolecular electron-transfer reaction from the viologen radical cation to the iron(III) center.
3) Syntheses and Characterizations of a New Type of Viologen-Linked N-Alkylporphyrin and Its Zinc(II) Complex-New type of viologen-linked tetraphenylporphyrin and its zinc(II) complex containing an N-trimethylene bridge were synthesized and characterized by a two dimensional ^1H-NMR spectroscopy. The decay of the porphyrin-based fluorescence was fitted by two
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exponentials, suggesting the presence of two conformers with respect to the orientation of viologen.
4) Photoinduced Electron-Transfer Reactions of Zinc and Magnesium Myoglobins-Both photoinduced electron-transfer and thermal backward electron-transfer reactions of zinc and magnesium myoglobins with cationic quenchers were bimolecular steps and the reaction rates were insensitive to the driving force of reactions, suggesting that the reactions are controlled by conformational changes of myoglobins. The intramolecular photoinduced electrontransfer was observed in a zinc myoglobin-hexacyanoferrate(III) complex, which forms by electrostatic interactions, and was inhibited in addition of poly-L-lysine by forming a stable complex of poly-L-lysine and hexacyanoferrate(III) ions.
5) Syntheses and Characterizations of Optical Active Viologens-Optical acitive viologens (OAV^<2+>) were newly synthesized and characterized. The stereoselectivity was found for the formation of the charge-transfer complex of OAV^<2+> with an L-ascorbate ion and for the ion-pair formation between OAV^<2+> and poly-L-glutamate ion. Less
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