EPR STUDIES OF RADICALS IN BIOLOGICAL CATALYSIS

描述：本研究提出的远景目标 应用是为了了解几种酶的催化机理 使用先进的电子顺磁共振(EPR)波谱 方法探索其催化剂的详细电子结构 并了解这些系统如何控制化学物质 反应性。要研究的酶是含铜胺 氧化酶，甲胺脱氢酶，甲基丙二酰辅酶A变位酶， 和一氧化碳脱氢酶。所有这些蛋白质都催化 在某一点上涉及顺磁中间态的反应 在他们的周期中。这项工作将涉及进一步的开发和使用 脉冲和双共振EPR实验测量磁性和 未配对的电子自旋之间的电子相互作用 瞬变顺磁物种和组成的磁核 他们的环境。这种超精细联轴器提供了一种直接测量 顺磁中心的最高占据分子轨道和 从而产生关于价电子分布的信息，即 参与催化的。这样的信息很难或不可能 通过其他光谱方法和X射线结晶学获得。是这样的 信息将与动力学和其他结果相关联 结构测量。特别是，结果将与 电子转移氧化/还原过程。

DESCRIPTION: The long range objectives of the research proposed in this application are to understand the catalytic mechanisms of several enzymes by using advanced electron paramagnetic resonance (EPR) spectroscopic methods to probe the detailed electronic structure of their catalytic sites and to gain an understanding of how these systems control chemical reactivity. The enzymes to be studied are copper-containing amine oxidases, methylamine dehydrogenases, methylmalonyl Coenzyme A Mutase, and carbonmonoxide dehydrogenase. All of these proteins catalyze reactions that involve paramagnetic intermediate states at some point during their cycle. This work will involve further development and use of pulsed and double resonance EPR experiments to measure magnetic and electronic interactions between the unpaired electron spin of the transient paramagnetic species and the magnetic nuclei that comprise their environment. Such hyperfine couplings provide a direct measurement of the highest occupied molecular orbital of the paramagnetic center and thus yield information on the valence electron distribution that is involved in catalysis. Such information is difficult or impossible to obtain by other spectroscopic methods and by X-ray crystallography. Such information will be correlated with the results of kinetic and other structural measurements. In particular the results will be related to electron transferring oxidation/reduction processes.