Physiochemical Studies on Xanthine Oxidizing Enzymes

梅西博士正在继续他对牛奶黄嘌呤氧化酶的研究，在这项研究中，他将检查该酶的四个氧化还原中心的化学、物理和结构特性，以及它们之间的相互作用。该项目还将包括与两种密切相关的酶-奶酶的脱氢酶形式和鸡肝中稳定的黄嘌呤脱氢酶-的比较研究。主要将使用停流光学技术来监测不同条件下氧化还原中心的氧化和还原，以及广泛使用13CNMR来研究底物、产物和缓蚀剂与钼中心的相互作用。黄嘌呤氧化酶是一种研究广泛的含钼羟基酶，对该酶的研究处于我们建立钼中心结构和作用于这一小类但重要的酶的化学机制的最前沿。由于黄嘌呤氧化酶含有至少四个能够可逆地吸收还原当量的中心，因此在更复杂的光合作用和线粒体电子传递系统中，该酶也可以作为氧化还原活性中心相互作用的有用模型。***

Dr. Massey is continuing his study of milk xanthine oxidase in which the chemical, physical and structural properties of the four redox centers of the enzyme and the interactions between them will be examined. The project will also include a comparative study with two closely related enzymes, the dehydrogenase form of the milk enzyme and the stable xanthine dehydrogenase from chicken liver. Major use will be made of stopped flow optical techniques to monitor oxidation and reduction of the redox centers under various conditions as well as extensive use of 13C NMR to study the interaction of substrates, products and inhibitors with the molybdenum center. Xanthine oxidase is a well-studied molybdenum-containing hydroxylase and studies on the enzyme lie at the forefront of our efforts to establish the structure of the molybdenum centers and the chemical mechanisms operative in this small but important class of enzymes. Because xanthine oxidase contains no fewer than four centers capable of reversibly taking up reducing equivalents, the enzyme also serves as a useful model for the interaction of redox-active centers in the more complicated systems of photosynthetic and mitochondrial electron transport. ***