| Co-Investigator(Kenkyū-buntansha) |
TOMINAGA Masato Kumamoto University, College of Medical Science, Research Associate, 医療技術短期大学部, 助手 (70264207)
NISHIYAMA Katsuhiko Kumamoto University, Faculty of Engineering , Assistant Professor, 工学部, 講師 (10202243)
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| Research Abstract |
In the present study, using surface modified single crystal gold electrodes and other functionalized electrodes, electron transfer reactions and biological functions of metalloproteins have been examined.
1. Using thermo-stable Chlorella ferredoxin as an electron transfer mediator of enzyme, artificial photosynthetic electrodes, on which enzyme and ferredoxin were co-immobilized in poly-peptide thin films, were prepared.
2. Functional electrode surfaces modified with SAMs of 2-, 3-, and 4-pyridinethiols and 2,2' and 5,5' pyrimidinethiols were examined at molecular level to understand their structures and functions for electron transfer reactions of metalloproteins by STM, surface-enhanced IR absorption spectroscopy (SEIRAS), surface-enhanced Raman spectroscopy (SERS), impedance measurement, contact angle measurement, the electrochemical reductive desorption technique, etc. On the Au(111) surface, for example, adsorbed 4 pyridinethiol (4-PySH) showed the rectangular unit cell of p(5 x 【sq
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uare root】3R-30°) structure with an interaction of two neighboring 4-PySH, while the 2-PySH modified electrode showed a p(4 x 【square root】7R-40.9°) structure with no dimer formation. 3-PySH showed a p(6 x 【square root】3R-30°) structure. Similar structures were also observed on the Au(100) surface. The observed electrochemical response of cytochrome c can be explained in terms of the observed structures of modified electrodes. However, properties of the surfaces required for the rapid electron transfer depended on metalloproteins used.
3. Using highly hydrophilic surface of In2O3 electrodes, biological functions and electron transfer kinetics of native and reconstituted myoglobins were examined in light and heavy water. The rates of electron transfer reactions of myoglobins were related to the porphyrin backbone of the heme, type of metal ion of the redox center, coordination structure etc. Biological functions depended on heme structures. New reconstituted myoglobin molecules having biological functions better than native myoglobin were also prepared.
4. A new artificial heme-incorporated polypeptide was prepared, and modified on the electrode surface to give electron-transfer reactions similar to a metalloprotein. Less
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