MITOCHONDRIAL MEMBRANE METABOLIC ROLE OF CYTOCHROME C

细胞色素c是线粒体中唯一的大分子成分 呼吸链，不是内分泌系统的一个组成蛋白质 线粒体膜，而是可以很容易地从外部解离 膜表面进入膜间空间。 丰富的 有关于其运作的许多方面的资料，但 仍然存在对力学基本方面的知识缺乏 其在正常细胞内生理条件下的功能， 这些是否与线粒体的各种状态有关， 呼吸链功能 因此，电子在 还原酶和氧化酶，细胞色素c的主要但不是唯一的功能， 可以在蛋白质（固态）几乎不运动的情况下发生 模型），通过沿内表面的外表面沿着二维扩散 线粒体膜，通过膜间隙中的自由扩散，或 通过这些过程的组合。 这种概念是由 动态聚集模型，假设自由扩散和 所有电子转移成分的相关形式，因此， 细胞色素c功能所需的迁移率将取决于 这种分离和关联形式的平衡。 来描述其 生理功能，建议：（1）采用新开发的一套 异构细胞色素c衍生物，以确定，通过共价键 交联，细胞色素c上电子接受位点的数量 氧化酶、细胞色素c过氧化物酶和其它电子交换伙伴， 建立了细胞色素c结合位点与其 采用差示共振拉曼光谱技术 光谱学研究细胞色素c和细胞色素c之间的相互作用 氧化酶以及细胞色素c过氧化物酶，并确定准确的结合 羧基修饰酵母细胞色素c的研究 过氧化物酶和细胞色素b5，以验证其定位 细胞色素c的相互作用结构域;（4）获得具有任何 通过重组DNA程序进行所需的氨基酸残基交换，和 利用它们来检查那些指定非凡的结构 酵母细胞色素c过氧化物酶的功能适应， 偶极矩和血红素平面之间的恒定角度的意义， 灵长类和非灵长类细胞色素的功能差异 （5）研究细胞色素c的生物合成， 将标记的细胞色素c引入完整的线粒体中。

Cytochrome c is the only macromolecular component of the mitochondrial respiratory chain that is not an integral protein of the inner mitochondrial membrane, but rather can readily dissociate from the outer surface of that membrane into the intermembrane space. A wealth of information is available concerning many facets of its operation, but there still exists a lack of knowledge about fundamental aspects of the mechanics of its function under normal intracellular physiological conditions, and whether these are correlated with the various states of mitochondrial respiratory chain function. Thus, the transfer of electrons between reductase and oxidase, the major but not the only function of cytochrome c, could take place with very little movement of the protein (solid state model), by two dimensional diffusion along the outer surface of the inner mitochondrial membrane, by free diffusion in the intermembrane space, or by combinations of these processes. Such a concept is provided by the dynamic aggregate model which postulates both freely diffusing and associated forms of all electron transfer components, so that the degree of mobility required for cytochrome c function will depend on the proportional equilibrium of such dissociated and associated forms. To describe its physiological function is it proposed to: (1) Employ a newly developed set of isomeric cytochrome c derivatives to determine, by covalent cross-linking, the number of electron-accepting sites on cytochrome c oxidase, cytochrome c peroxidase and other electron exchange partners, establishing the relation between the site of cytochrome c binding and its effect on the kinetics of reaction; (2) employ difference resonance Raman spectroscopy to study the interaction between cytochrome c and cytochrome oxidase as well as cytochrome c peroxidase, and determine accurate binding affinities in solution; (3) study carboxyl-modified yeast cytochrome c peroxidase and cytochrome b5 to verify the localization of their interaction domains for cytochrome c; (4) obtain cytochromes c with any desired amino acid residue exchange by recombinant DNA procedures, and employ them to examine the structures that specify the remarkable functional adaptation of yeast cytochrome c peroxidase, the functional significance of the constant angle between dipole moment and heme plane, and the functional difference between primate and non-primate cytochromes c; (5) study the biosynthesis of cytochrome c to develop procedures for introducing labelled cytochrome c into intact mitochondria.