Foundamental Studies on Bioelectric Devices

细胞色素C_3是一种具有四个血红素的电子传递分子，由于其独特的电化学和电学性质，是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固态膜和固定在电极表面的细胞色素单分子层的性质，细胞色素C_3固态膜的霍尔迁移率非常小，与其氧化态无关。膜在完全氧化状态下的电阻率为10^<13>OMEGAcm。对组氨酸和一个苯丙氨酸残基的NMR信号进行了归属。通过紫外-可见反射光谱的测定发现：（1）马心细胞色素c吸附在裸露表面上，保持其天然的氧化还原活性，但在短时间内氧化还原活性消失;和（2）具有羧基末端基团的硫醇分子表现出调节细胞色素C_（1-x）的氧化还原电位的功能。3.由于Soret带的共振效应，固定在双（4-吡啶）二硫键修饰银电极上的细胞色素c的拉曼散射信号可以被选择性地观测到。利用拉曼散射技术分析了细胞色素c血红素铁的自旋和配位态。

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.