1997 Fiscal Year Final Research Report Summary
Electron-Transfer Reactions of Chemically Modified Hemoproteins and Their Model Compounds
| Project/Area Number |
08454209
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Inorganic chemistry
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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, Professor, 理学部, 教授 (70112117)
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| Co-Investigator(Kenkyū-buntansha) |
KATO Masako Nara Women's University, Department of Chemistry, Associate Professor, 理学部, 助教授 (80214401)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Modified Myoglobin / Co(III) Attached Myoglobin / Photo-Induced Electron Transfer / N-Alkylporphyrin / Quinoline / Diethylenetriaminepentaacetic Acid / Viologen / Aminopolycarboxylate |
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| Research Abstract |
1) Metmyoglobin modified with diethylenetriaminepentaacetic acid (metMbDTPA) binds Cu(II) and Co(II) to form metMb{Cu^<II>(dtpa)} and metMb{Co^<II>(dtpa)}, respectively. The latter was further oxidized by K_3[Fe(CN)_6] to form metMb{Co^<III>(dtpa)}. These compounds were characterized by an ESR and an atomic absorption spectro-scopies and a cyclic voltammetry. 2) The intra- and intermolecular electron-transfer reactions of one electron-reduced deoxyMb{Co^<III>(dtpa)} were investigated by spectrophotometrically. The intramolecular electron-transfer reaction depends on the attached site of DTPA.3) The heme iron of metMbDTPA was replaced by a Zn(II) ion and the excited singlet and triplet states of ZnMbDTPA were efficiently quenched by a bound Cu(II) ion. The excited triplet state of ZnMbDTPA was also quenched intramolecularly by the oxidized form of cytochrome c. 4) Viologen or quinoliniumlinked N-alkylporphyrin dyads were synthesized and characterized. The orientation and distance effects on the rates of the quenching and photo-induced electron-transfer reactions were investigated in acetonitrile and propylene glycol. Orthogonal orientation of viologen or quinolinium ion against the porphyrin plane decelerated the electron- and energy-transfer reaction rates. 5) The stereoselective electron-transfer reactions between hemoproteins and chiral viologen-radical cations were investigated. The (S,S) -isomers of chiral viologens preferentially reduced metmyoglobin and cytochrome c.
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Research Products
(13 results)
