Adsorptive immobilization of cytochrome c on indium/tin oxide (ITO):: electrochemical evidence for electron transfer-induced conformational changes
Adsorptive immobilization of cytochrome c on indium/tin oxide (ITO):: electrochemical evidence for electron transfer-induced conformational changes
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DOI：
10.1016/s1388-2481(01)00299-5
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发表时间：
2002-02-01
影响因子：
5.4
通讯作者：
Bowden, EF
中科院分区：
文献类型：
--
作者：
El Kasmi, A;Leopold, MC;Bowden, EF
报道了马和酵母细胞色素c在铟锡氧化物（ITO）电极上的吸附固定及其电化学行为。近单层覆盖实现在pH值为7的磷酸盐缓冲液的离子强度等于10和50 mM，分别为马和酵母物种。这些层表现出非常良好的伏安法，并且在数小时至数天的时间尺度上是稳定的。循环伏安法显示准可逆行为，这是一个产品的电子转移（ET）动力学和ET诱导的构象变化。提出了一个连接氧化还原态和构象态的平方机制。使用一个简单的ET动力学模型，充分描述了伏安法在较高的扫描速率，一个标准的ET速率常数为18秒（-1）被确定为吸附的马细胞色素c。随着扫描速率的降低，我们观察到约10 mV的极限峰分离，这是我们归因于构象变化影响的不寻常准可逆性（UQR）的一个例子。最后，我们注意到，ITO上的固有细胞色素c ET率比金低约6个数量级。(C)2002年由Elsevier Science B. V.出版
The adsorptive immobilization and electrochemistry of horse and yeast cytochrome c on indium/tin oxide (ITO) electrodes is reported. Near-monolayer coverage was achieved in pH 7 phosphate buffers of ionic strength equal to 10 and 50 mM, respectively, for the horse and yeast species. The layers exhibit very well-behaved voltammetry and are stable on the timescale of hours to days. Cyclic voltammetry revealed quasireversible behavior that is a product of both electron transfer (ET) kinetics and ET-induced conformational changes. A square scheme mechanism linking the redox states and the conformational states is proposed. Using a simple ET kinetic model that adequately describes the voltammetry at higher scan rates, a standard ET rate constant of 18 s(-1) was determined for adsorbed horse cytochrome c. With decreasing scan rate, we observed a limiting peak separation of approximately 10 mV, an example of unusual quasireversibility (UQR) that we attribute to the effect of conformational changes. Finally we note that the intrinsic cytochrome c ET rate on ITO is some 6 orders of magnitude less than for gold. (C) 2002 Published by Elsevier Science B.V.