Kinetics and mechanisms of reduction of rusticyanin, a blue copper protein from Thiobacillus ferrooxidans, by inorganic cations
Kinetics and mechanisms of reduction of rusticyanin, a blue copper protein from Thiobacillus ferrooxidans, by inorganic cations
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无机阳离子还原氧化亚铁硫杆菌的蓝铜蛋白 rusticyanin 的动力学和机制
DOI：
10.1021/ic00204a008
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发表时间：
1985
影响因子：
4.6
通讯作者：
W. Ingledew
中科院分区：
文献类型：
--
作者：
A. Lappin;C. A. Lewis;W. Ingledew
研究了氧化亚铁硫杆菌蓝铜蛋白的氧化还原反应。使用4，4‘-联吡啶修饰的碳糊电极的循环伏安法给出蛋白质的还原电位为0.67V(vs.NHE)，与pH无关。铁(II)还原黄曲霉素铜(II)的动力学研究显示阴离子效应。在氯化物介质中，反应速率与Fe(II)浓度的关系为一级反应，而在硫酸盐存在时，反应速率与Fe(II)浓度的关系为极限零级动力学。没有钴(II)离子的抑制表明这是由于限速蛋白构象的变化。虽然与铁(II)的反应很慢，但与生理上重要的相互作用并不矛盾。相比之下，铬(II)的还原速度很快，与其他蓝铜蛋白的反应相当。
Oxidation-reduction reactions of the blue copper proteinrusticyanin from Thiobacillus ferrooxidans have been investigated. Cyclic voltammetry using a 4, 4'-bipyridyl-modified carbon-paste electrodegives a reduction potential of 0.67 V (vs. NHE) for the protein, independent of pH in the range 1-3. Kinetic studies of the reduction of the copper (II) form of rusticyanin by iron (II) show anion effects. The dependence of reaction rate on iron (II) concentration Is first order in chloride media but shows limiting zero-order kinetics in the presence of sulfate ion. The absence of inhibition by cobalt (II) ion suggests that this is due to a rate-limiting protein conformational change. Although the reaction with iron (II) is slow, it is not inconsistent with an interaction of physiological importance. In contrast, reduction by chromium (II) is rapid and comparable with reactions of other blue copper proteins.