PEROXIDASES, CATALASES, AND CYTOCHROME P-450

过氧化物酶、过氧化氢酶和细胞色素 P-450

• 批准号: 3300269
• 负责人: ZBIGNIEW R KORSZUN
• 金额: $ 3.67万
• 依托单位: UNIVERSITY OF WISCONSIN PARKSIDE
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-04-01 至 1992-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3300269
• 关键词: X ray crystallography; catalase; catalyst; cytochrome P450; cytochrome oxidase; heme; oncogenes; oxidation; peroxidases; stereochemistry; toxicology

Polarized EXAFS and XANES studies on single crystals of several heme enzymes and model compounds will be-performed. The heme en- zymes include resting and camphor-bound cytochrome p-450 from Ps. putida, and the resting form of yeast cytochrome c peroxidase as well as its cyanide adduct and enzyme-substrate complex. These heme enzymes catalyze a diverse series of rections. Cytochrome c peroxidase catalyzes the breakdown of organic peroxides and ex- hibits catalytic intermediates which are similar in structure and function to catalase and horse radish peroxidase. The cytochromes P-450 catalyze a mixed function bond-breaking of hydrocarbons by cleaving molecular oxygen. This class of enzymes is characterized by a diverse selectivity of substrates and cytochromes P-450 are found in regulatory, oncogenic, and toxological systems. Both the peroxidases and cytochrome P-450 share stereochemical aspects of their catalytic mechanisms and they are similar in certain respects to mitochondrial cytochrome oxidase. A polarized EXAFS study of these enzymes will complement x-ray crystalloqrahic and solution EXAFS studies by providing highly accurate heme in-plane and axial geometries of the catalytic intermediates which are stable in the crystal. ln addition, the measurement of polarized XANES spectra on these enzymes and models coupled with X-Alpha Scattered Wave molecular orbital calculations will provide a description of the electronic basis for catalysis by these enzymes. Finally, the polarized EXAFS and XANES experiments on the model compounds and enzymes will provide a detailed stereochemical decription of the heme second and third nearest neiqhbors.

几种单晶的极化EXAFS和XANES研究 血红素酶和模型化合物。 血红素- 酶包括来自Ps的静息和底物结合的细胞色素p-450。 putida和酵母细胞色素c过氧化物酶的静息形式， 以及其氰化物加合物和酶-底物复合物。 这些 血红素酶催化多种反应。 细胞色素c 过氧化物酶催化有机过氧化物的分解， Hibits催化中间体在结构上类似， 过氧化氢酶和辣根过氧化物酶的功能。 细胞色素 P-450催化烃的混合功能键断裂， 裂解氧分子 这类酶的特征在于 通过底物和细胞色素P-450的不同选择性， 在调节、致癌和毒性系统中发现。两者 过氧化物酶和细胞色素P-450共享立体化学方面， 它们的催化机制在某些方面是相似的 到线粒体细胞色素氧化酶。 极化EXAFS研究 这些酶将补充X射线晶体学和溶液 EXAFS研究通过提供高度精确的血红素平面和轴向 催化剂中间体的几何形状是稳定的， 水晶 此外，还测量了这些样品的偏振XANES谱， 酶和模型与X-α散射波分子耦合 轨道计算将提供电子的描述 这些酶催化的基础。 最后，对模型进行了极化EXAFS和XANES实验 化合物和酶将提供详细的立体化学 血红素第二和第三近邻的描述。

项目成果

On the structure of the nickel/iron/sulfur center of the carbon monoxide dehydrogenase from Rhodospirillum rubrum: an x-ray absorption spectroscopy study.

红色红螺菌一氧化碳脱氢酶镍/铁/硫中心的结构：X 射线吸收光谱研究。

• DOI: 10.1073/pnas.89.10.4427
• 发表时间: 1992
• 期刊: Proceedings of the National Academy of Sciences of the United States of America
• 影响因子: 11.1
• 作者: Tan,GO;Ensign,SA;Ciurli,S;Scott,MJ;Hedman,B;Holm,RH;Ludden,PW;Korszun,ZR;Stephens,PJ;Hodgson,KO
• 通讯作者: Hodgson,KO