METAL SULFUR & METAL CARBOXYLATE SITES IN REDOX ENZYMES

生物系统中的电子转移与氧化和 生物体中各种底物的还原是 对维持生命的过程至关重要。多个- 电子转移过程，尽管在性质上不太频繁，但 同样重要的是。后者包括：4E- 光合作用中2H20氧化为02，6E-还原 氮气在固氮酶中还原为氨，亚硫酸盐的6E-还原为 亚硫酸盐和亚硝酸盐还原酶中硫化物和亚硝酸盐转化为氨 分别进行了分析。在参与其中的各种酶中表现突出 底物的氧化或羟化是甲烷 单加氧酶，MMO。这种酶催化氧化 甲烷转化为甲醇的活性中心，不像细胞色素P- 450，不利用铁卟啉中心。 这项建议涉及到对……的合成和研究 A)涉及多电子的金属酶的合成类似物 还原和b)氧化中活跃的非卟啉中心 和有机底物的羟基化。具体来说： 新化合物的合成、结构、光谱性质及反应活性 Fe/M/S(M=Mo，W，V)和Fe/S团簇有望提供服务 作为固氮酶中Fe/M/S中心的合成类似物 含钒或铁的替代固氮酶 钼。Fe/S团簇的新类型将是 被设计为P-团簇的模型 固氮酶。添加Fe/S的超分子组装 将合成簇合物作为活性中心的可能模型 在亚硫酸盐和亚硝酸盐还原酶中。低聚化合物是已知的， 或被认为参与了诸如氧化等过程 甲烷在MMO(M=Fe)中转化为甲醇与光合作用 将水氧化成02(M-Mn)。单体、混配 羧酸盐复合体也参与了酶的氧化。 如邻苯二酚功能氧化为顺式肉豆蔻酸 苯丙氨酸的芳环羟基化为酪氨酸 通过与氧气反应，(M=Fe)。羧酸盐络合物 第一行元素将作为结构和反应性进行研究 酶中催化氧化的活性部位模型 不同的底物。

Electron transfer in biological systems and the oxidation and reduction of various substrates in living organisms are of fundamental importance to life sustaining processes. Multi- electron transfer processes, although less frequent in nature are of equally great importance. Included among the latter are: The 4e- oxidation of 2H20 to 02 in photosynthesis, the 6e- reductions of N2 to ammonia in nitrogenase, and the 6e- reduction of sulfite to sulfide and of nitrite to ammonia in sulfite and nitrite reductases respectively. Outstanding among the enzymes involved in the oxidation or hydroxylation of substrates is methane monooxygenase, MMO. This enzyme catalyzes the oxidation of methane to methanol at an active site that, unlike cytochrome P- 450, does not utilize an Fe-porphyrin center. This proposal is concerned with the synthesis and study of synthetic analogs for a) metalloenzymes involved in multielectron reduction and b) the non-porhyrin centers active in the oxidation and hydroxylation of organic substrates. Specifically: the synthesis, structures, spectroscopic properties and reactivities of Fe/M/S (M=mo, W, V) and Fe/S clusters are expected to serve as synthetic analogs for the Fe/M/S centers in the nitrogenases and alternate nitrogenases that contain vanadium or iron in place of molybdenum. The new types of Fe/S clusters that will be synthesized are designed as models for the P-clusters of nitrogenase. Supramolecular assemblies with appended Fe/S clusters will be synthesized as possible models for the active sites in sulfite and nitrite reductase. Oligomeric complexes are known, or believed to be, involved in processes such as the oxidation of CH4 to methanol in MMO (M =Fe) and the photosynthetic oxidation of water to 02(M -Mn). Monomeric, mixed-ligand carboxylate complexes also are involved in enzymatic oxidations such as the oxidation of the catechol function to cis muconic acid and the aromatic ring hydroxylation of phenylalanine to tyrosine via reaction with dioxygen, (M =Fe). Carboxylate complexes of first row elements will be studied as structure and reactivity models for the active sites in enzymes that catalyze the oxidation of various substrates.