MECHANISTIC PROBES FOR ENZYME CATALYZED OXIDATIONS

研究的总体目标是阐明其作用机制。 催化碳氢化合物和胺氧化的酶。前者 基团包括血红素硫酸盐细胞色素P450酶和二铁酶 如甲烷单加氧酶和硬脂酰去饱和酶。后一组 包括单胺氧化酶(MAO)酶和P450酶。一个 对这些酶的作用机制的了解有望 有利于治疗进展，例如，MAO是靶点 治疗抑郁症和帕金森氏病的药物的酶。 研究方法包括使用“超敏感”自由基探针。 可用作氧化反应的底物，以揭示中间体 非常短暂的激进分子。设计了探头基板，并对其性能进行了测试。 测定了自由基反应速率常数。来自产品分发 在酶的氧化作用中，自由基的中间体是确定的，如果 自由基是中间体，自由基的寿命是可以测量的。 为了研究含铁酶对碳氢化合物的氧化作用，一些 超敏探头现已存在，其他探头的发展是 有计划的。特别值得注意的是一系列探测器，它们区分了 在自由基中间体和阳离子中间体之间保持敏感 自由基反应中的反应性。酶催化的氧化反应 PI的实验室正在使用酶进行校准的探针 由其他组和在其他组的实验室中使用 由PI小组提供的探头。预计结果将勾勒出 反应机理的共性和不同之处 看似独特的酶。 对于酶催化的胺氧化的研究，这项工作是在更多的 基本阶段。大范围氮气反应的动力学标度 含有自由基的是通过直接、激光的组合测量的 闪光光解方法和间接动力学竞争技术。什么时候 了解含氮自由基的反应， 合理设计的机械式测头将在 P450和MAO酶的氧化反应。

The overall goal of the research is to elucidate the mechanisms of action of enzymes that catalyze oxidations of hydrocarbons and amines. The former group includes the heme-thiolate cytochrome P450 enzymes and diiron enzymes such as methane monooxygenase and stearoyl desaturase. The latter group includes the monoamine oxidase (MAO) enzymes as well as P450 enzymes. An understanding of the mechanisms of actions of these enzymes is expected to be beneficial for therapeutic advances, for example, MAO is the target enzyme of drugs for treatment of depression and Parkinson's Disease. The method of study involves the use of "hypersensitive" radical probes that can be employed as substrates in oxidations to reveal the intermediacy of very short-lived radicals. The probe substrates are designed, and the radical reaction rate constants are determined. From product distributions in enzyme oxidations, the intermediacy of a radical is determined, and, if a radical is an intermediate, the lifetime of the radical is measured. For studies of hydrocarbon oxidations by iron-containing enzymes, some hypersensitive probes now exist, and the development of other probes is planned. Especially noteworthy is a family of probes that distinguish between radical and cationic intermediates while maintaining hypersensitive reactivity in the radical reaction. Enzyme catalyzed oxidations of calibrated probes are in progress in the PI's laboratory, using enzymes purified by other groups, and in the laboratories of other groups, using probes supplied by the PI's group. The results are expected to delineate common and dissimilar features in the mechanisms of reactions of the seemingly distinct enzymes. For studies of enzyme catalyzed amine oxidations, the work is at a more fundamental stage. Kinetic scales for reactions of a wide range of nitrogen containing radicals are being measured by a combination of direct, laser flash photolysis methods and indirect kinetic competition techniques. When the reactions of the nitrogen containing radicals are understood, rationally designed mechanistic probes will be developed and applied in oxidation reactions by P450 and MAO enzymes.