1990 Fiscal Year Final Research Report Summary
Photo and Magneto-Chemical Studies on Microstructure and Function of Active Sites
| Project/Area Number |
01470050
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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 | Kyoto University |
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Principal Investigator |
OHYA Hiroaki Kyoto Univ., Fac. Science Ass. Professor, 理学部, 助教授 (00025389)
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| Co-Investigator(Kenkyū-buntansha) |
KOHNO Masahiro Jeol Co. Ltd., Aite Div., Manager, 分析機器技術本部, 副課長
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| Project Period (FY) |
1989 – 1990
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| Keywords | Enzymatic Model / Enzynatic Reaction / Intermediate / ESR / ESRET / Multichannel Photometer / SOD / Peroxide Adduct |
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| Research Abstract |
Photo- and magneto-chemical studies on microstructure and function of the active sites in typical enzymes have been carried out by using a simultaneous ESR and optical measurement apparatus (ESRET) developed by this project. 1) Fe (tpp) Cl was employed as a model complexes of heme-Fe^<3+> proteins. This complex showed a clear formation of a peroxide adduct of Fe (tpp)(OOR), which is a key intermediate to function as several enzymatic reaction. The ESR and absorption spectra exhibit characteristic features of its formation. 2) By using the Co^<3+>-polyamine and Co^<2+>-(SB)(SB : Shiff base) as models of dioxygenases we have examined reaction mechanisms of catechol dioxygenase reactions. The former complex formed a binary complex with catechols, followed by an addition of O_2 resulting in a ternary complex. In the latter O_2 first formed an oxygen adduct with the complex, and occurred an intramolecular electron transfer reaction. Secondly, catechol as a substrate was oxydized by the cobalt complex to semiquinone. 3) As a typical example of Fe-SOD model Fe^<3+>-EDTA and its analogs were reacted with active oxygen species. It was found by ESRET that two intermediates are formed : One is sideon type Fe^<3+>-O_2^<2-> and the other Fe^<2+>-O_2^-. By using these intermediates as probes of the recation, the reaction mechanism of the SOD was investigated.
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