BIOLOGICAL VANADIUM--MODELS OF STRUCTURE AND REACTIVITY

我们设置了泡沫程序来评估钒在+3，+4中的化学 和+5个氧化态，使用被设计成结合 生物上相关的杂原子捐赠者。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以及非氧化还原的作用。对钒作为一种金属的认识 在过去的五年里，生物学中的重要元素有了很大的增加 由于分离出了第一种含钒的酶，已经有好几年的时间了。之前 在这一时期，钒在某些固着的物种中是稀有的。 被囊类和有毒蘑菇中的一种。钒也是 已知是作为磷酰化转移抑制剂的磷酸盐模拟物 酶、ATPase和作为胰岛素激活剂。现在已经确定，一个 单核钒(V)催化卤代过氧化物酶化学 仅限于亚铁血红素或非亚铁血红素酶。此外，还出现了钒 取代含钒固氮酶中的钼。它是 特别有可能的是，随着海洋生物无机化学的发展 需要钒的酶可能会被发现。所描述的化学物质 在此将开发和检查活动站点结构的模型和 藻类溴过氧化物酶的化学机制。每个新隔离的 材料将接受化学分析，如X射线 结晶学、EPR、核磁共振、UV-Vis光谱和电化学。这个 我们第二阶段的工作将评估钒的结合性能 植物铁载体和铁载体类似物。这个项目的目标是 建立土壤对钒的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...的发展 高核度团簇中的钒化学。虽然目前 未知的，它是在可能的领域内，双核钒 人们将会发现类似于双核铁的酶， 锰或铜酶。我们的最后一个话题是钒的反应性。 络合物在氧化还原中的作用和对锰/钒的进一步探索 两个电子有机转化的反应性类比。这个 从这些研究中收集的信息将为 关于钒的适当指导原则，使我们处于更有利的地位 用一个基本概念来定义已知生物过程的化学 此元素的要求。

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.