BIOLOGICAL VANADIUM--MODELS OF STRUCTURE AND REACTIVITY

我们建立了froth程序来评估+3，4中钒的化学性质 和+5氧化态，其使用被设计为结合 生物学上相关的杂原子供体。 我们的目标是定义基本的 钒的配位性质及其反应模式， 氧化还原和非氧化还原和非氧化还原作用。 对钒作为一种 在过去的五年里，生物学中的一个重要元素大大增加了。 年，由于第一个含钒酶的分离。 之前 到这一时期，钒在某些固着物种中是一种好奇心， 被囊类和毒蘑菇A.蝇虫范德堡也是 已知是一种磷酸盐模拟物，用作磷酰基转移抑制剂 酶、ATP酶和作为胰岛素激活剂。 现在已经确定， 单核钒（V）催化卤过氧化物酶化学以前 仅限于血红素或非血红素铁酶。 此外，钒出现 以取代含钒固氮酶中的钼。 是 特别可能的是，随着海洋生物无机化学的发展， 需要钒的酶可能未被发现。 描述的化学 本文将开发和研究活性位点结构的模型， 藻类溴过氧化物酶的化学机制。 每一个新分离的 材料将进行化学分析，如X射线 晶体学、epr、NMR、UV-vis光谱和电化学。的 我们的第二阶段工作将评估钒的结合性能 植物铁载体和铁载体类似物。 该项目旨在 建立了钒吸收和积累的可能机制， 植物和细菌细胞。 第三个研究领域是 高核团簇中的钒化学。 虽然目前 未知的，这是在可能性的范围内，双核钒 将发现可能类似于双核铁的酶， 锰或铜酶。 我们最后的主题是钒的反应性 研究了锰钒配合物的氧化还原作用， 两个电子有机转换的反应性类比。 的 从这些研究中收集的信息将奠定基础， 对钒有足够的指导原则，使我们处于更有利的地位 定义已知生物过程的化学， 这一要素的要求。

We set froth program to evaluate the chemistry of vanadium in the +3, +4 and +5 oxidation states using ligands that are designed to incorporate biologically relevant heteroatom donors. Our goal is to define the basic coordination properties of vanadium and its reactivity patterns both in redox and non-redox and non-redox roles. The recognition of vanadium as an important element in biology has increased considerably in the last five years due to the isolation of the first vanadium containing enzymes. Prior to this period, vanadium was a curiosity in certain species of sessile tunicates and in the poisonous mushroom A. muscaria. Vanadium was also known to be a phosphate mimic acting as an inhibitor of phosphoryl transfer enzymes, ATPases and as an insulin activator. It is now established that a mononuclear vanadium (V) catalyzes haloperoxidase chemistry previously restricted to heme or non-heme iron enzymes. Furthermore, vanadium appears to substitute for molybdenum in the vanadium containing nitrogenase. It is especially likely that as marine bioinorganic chemistry develops additional enzymes requiring vanadium may be uncovered. The chemistry described herein will develop and examine models for the active site structure and chemical mechanism of the algal bromoperoxidases. Each newly isolated material will be subjected to chemical analysis such as X-ray crystallography, epr, NMR, UV-vis spectroscopies and electrochemistry. The second phase of our work will evaluate the binding properties of vanadium to phytosiderophores and siderophore analogs. This project is aimed at establishing possible mechanism of vanadium uptake and accumulation in plant and bacterial cells. The third area of study is the development of vanadium chemistry in higher nuclearity clusters. Although presently unknown, it is within the realm of possibilities that dinuclear vanadium enzymes will be discovered that may be analogous to dinuclear iron, manganese or copper enzymes. Our final topic is the reactivity of vanadium complexes in redox roles and exploring further the manganese/vanadium reactivity analogy for two electron organic transformations. The information gathered from these studies shall lay the foundation of adequate guiding principles for vanadium, placing us in a better position to define the chemistry of known biological processes with an essential requirement for this element.