Foundamental Studies on Bioelectric Devices

细胞色素C_3是一种每个分子含有4个血红素的电子转移体，由于其独特的电化学性质和电学性质，使其成为最有前途的生物电器件材料之一。本文研究了细胞色素C_3固体膜和固定在电极表面的细胞色素单层膜的表征。无论细胞色素C_3处于何种氧化状态，细胞色素C_3固态膜的霍尔迁移率都非常小。膜在完全氧化状态下的电阻率为10^&lt；13；gt；OMEGAcm。对Hystidine和一个苯丙氨酸残基的核磁共振信号进行了指认。对这些残基在分子内电子转移中作用的研究正在进行中。通过UV-Vis反射光谱测量发现：(1)吸附在裸表面上的马心细胞色素C保持其天然的氧化还原活性，这种活性在短时间内消失；(2)含有羧基的硫醇分子具有调节细胞色素C_3的氧化还原电位的功能。由于Soret带的共振效应，可以选择性地观察到固定在双(4-吡啶)二硫代银电极上的细胞色素C的拉曼散射信号。利用拉曼散射技术分析了细胞色素c中的血红素铁的自旋和配位状态。

Cytochrome C_3, an electron-transfer possessing four hemes per molecule, is one of the most promising materials of the bioelectric devices due to its specific electrochemical and electric properties. The present study is devoted to the characterization of cytochrome C_3 solidstate film and of the monolayer of cytochrome immobilized on the electrode surface.The Hall mobility of the cytochrome C_3 solid-state film was immeasurably small regardless of the oxidation state of cytochrome C_3. The resistivity of the film in its fully oxidized state was 10^<13> OMEGAcm.The assignment of the NMR signals of hystidine and one phenylalanine residues was established. The study on the roles played by these residues on the intramolecular electrontransfer is now underway.It was found from UV-vis reflectance spectroscopic measurement that (1) horse heart cytochrome c adsorbed on a bare surface maintains its native redox activity, which disappears after a short period, and (2) a thiol molecule possessing a carboxyl terminal group exhibits a function to regulate the redox potentials of cytochrome C_3.Raman scattering signals of cytochrome c immobilized on the bis(4-pyridyl) disulfidemodified silver electrode could be selectively observed due to the resonance effect at a wavelength of the Soret band. The spin and coordination states of heme iron of cytochrome c were analyzed using Raman scattering techniques.