COVALENT FLAVIN COENZYMES IN FLAVOENZYME CATALYSIS

这个项目的目标是寻求对一个分子的理解 关于某些新陈代谢重要的原因 氧化还原酶需要8α取代， 共价结合的黄素辅酶，而其他的不是。这个 使用的方法包括氧化还原和氧化还原的比较研究 两种胆固醇氧化酶的催化性质，其中一种 有一个正常的时尚，而其他的包含一个8阿尔法-N(1)- Histidyl时尚。氧化还原电位与温度的关系 PH值将对胆固醇氧化酶、硫胺素氧化酶和 8个α-取代的FMN-阿波黄素络合物，将被 延伸到线粒体琥珀酸脱氢酶，它包含 8α-N(3)-组氨酸时尚。机械学研究利用 定态和停流动力学技术将在 肝脏单胺氧化酶；一种神经药理作用的酶 在生物胺调节中的重要性，它包含一个8 阿尔法-S-半胱氨酸时尚。圆二向色性与恩多 光谱方法将被用来监测 黄素还原的蛋白质构象及其作用机制的探讨 几种不同共价态黄素基团的环境 酶系统。8个α-取代基在1-取代基中的作用 电子转移反应将用停流动力学来探讨 重组脂黄素-8α-FMN络合物的研究 这些研究的结果将是 线粒体电子传递的重要性以及在 重要酶作用机制的阐明 琥珀酸脱氢酶和单胺氧化酶等系统。

The goal of this project is to seek an understanding on a molecular basis as to the reason why certain metabolically important oxidation-reducton enzymes require an 8 alpha-substituted, covalently bound flavin coenzyme while others do not. The approaches to be used include a comparative study of redox and catalytic properties of the two cholesterol oxidases, one which has a normal FAD while the others contains an 8 alpha-N(1)- histidyl FAD. The dependence of oxidation-reduction potential on pH will be done on the cholesterol oxidases, thiamine oxidase and 8 alpha-substituted FMN-apoflavodoxin complexes and will be extended to mitochondrial succinate dehydorgenasewhich contains an 8 alpha-N(3)-histidyl FAD. Mechanistic studies utilizing steady-state and stopped-flow kinetic techniques will be done on liver monoamine oxidase; an enzyme of neuro-pharmacological importance in biogenic amine regulation which contains an 8 alpha-S-cysteinly FAD. Circular dichroism and ENDOR spectroscopic approaches will be used to monitor alterations in protein conformation on flavin reduction and probe the environments of the respective covalent flavin moieties in several enzyme systems. The role of the 8 alpha-substituent in one- electron transfer reactions will be probed by stopped-flow kinetic studies on reconstituted apoflavodoxin-8 alpha FMN complexes with cytchrome c. The results of these studies will be of importance in mitochondrial electron transport and in the elucidation of the mechanism of action of important enzyme systems such as succinate dehydrogenase and monoamine oxidase.