STRUCTURAL MODELS FOR MOLYBDOENZYMES

钼，一种必需的微量元素，是第二种中唯一的金属， 第三个过渡系列是所有生命形式所必需的。在 在人类中，氧化酶参与亚硫酸盐氧化（亚硫酸盐氧化酶） 和嘌呤代谢（黄嘌呤氧化酶）。致命的并发缺陷 这两种酶的活性由于先天缺乏， 一种常见的“钼辅因子”（Moco）现在在儿童中得到了很好的证明。 接触过量的钼与痛风有关， 缺乏可能会加剧对亚硫酸盐的敏感性。这个项目的总体目标是 研究的目的是了解这种物质的结构、功能和反应性， 生理上重要的含蝶呤的钼酶通过研究 模型化合物和酶本身。亚硫酸盐氧化酶是 生物无机、生物化学和生物物理化学家的基本兴趣 因为它提供了研究 钼辅因子，氧原子转移化学，分子内 在单个分子系统内的电子转移反应。研究 这里提出的解决这些基本问题，通过综合 合成，结构，光谱和反应性研究计划 模型化合物和亚硫酸盐氧化酶本身。 重点将放在 氘-铁模型化合物的合成与表征 亚硫酸盐氧化酶中的相互作用;电子自旋回波的发展 包络调制（ESEEM）光谱作为钼的探针 模型化合物和酶中的环境;研究分子内 亚硫酸盐的钼中心和铁中心之间的电子转移 氧化酶;以及启动亚硫酸盐结构的测定 氧化酶的X射线晶体学。

Molybdenum, an essential trace element, is the only metal in the second and third transition series that is essential for all forms of life. In humans, molybdoenzymes are involved in sulfite oxidation (sulfite oxidase) and purine metabolism (xanthine oxidase). Fatal simultaneous deficiencies in the activities of both of these enzymes due to an inborn deficiency of a common 'molybdenum cofactor' (Moco) are now well documented in children. Exposure to excess molybdenum has been linked with gout, and molybdenum deficiency may aggravate sensitivity to sulfite. The overall goal of this research is to understand the structure, function, and reactivity of this physiologically vital pterin-containing molybdenum enzyme through studies of model compounds and the enzyme itself. Sulfite oxidase is of fundamental interest to bioinorganic, biochemical and biophysical chemists because it provides opportunities to investigate the structure of the molybdenum cofactor, oxygen atom transfer chemistry, and intramolecular electron transfer reactions within a single molecular system. The research proposed here addresses these fundamental issues through an integrated program of synthetic, structural, spectroscopic and reactivity studies of model compounds and of sulfite oxidase itself. Emphasis will be given to the synthesis and characterization of models for the molybdenum-iron interaction in sulfite oxidase; to the development of electron spin echo envelope modulation (ESEEM) spectroscopy as a probe of the molybdenum environment in model compounds and enzymes; to studying intramolecular electron transfer between the molybdenum and iron centers of sulfite oxidase; and to initiating the determination of the structure of sulfite oxidase by X-ray crystallography.