摘要
采用循环伏安法、交流阻抗谱探讨了L -半胱氨酸自组装膜修饰金电极表面细胞色素c(Cytc)的电化学行为,Cytc在该电极表面的平均吸附量Г=1 .366×10-10 mol/cm2。紫外 可见吸收光谱法和电化学方法证实,通过静电作用固定在L 半胱氨酸自组装膜电极上的Cytc保持了良好的生物活性和电化学活性。在低扫速时峰电流与扫速呈线性关系,表明Cytc与电极之间是表面过程。通过交流阻抗谱求得在细胞色素c/L 半胱氨酸膜修饰金电极上的标准异相电子迁移速率常数k0s为 7 .529×10-4 cm/s。吸附到L 半胱氨酸自组装膜电极表面的Cytc对H2O2 的还原表现出良好的电催化效应,初步研究了电催化机理。Michaelis Menten常数为Kappm =1. 21×10-3 mol/L,与其它蛋白质相比,吸附在L Cys/Au膜电极上的Cytc对H2O2有较好的亲和力。
The electrochemical behavior of horse-heart cytochrome c(Cyt c) adsorbed on L -cys/Au electrode surface was investigated by means of cyclic voltammetry , ac impedance and ultraviolet spectrometric measurements. The average adso rbance of Cytochrome c on the membrane electrode surface is 1.366×10-10 mol/cm2. Cyt c immobilized on L-Cys/Au SAMs by electrostatic interac tion maintains biological activity and electrochemical activity. The voltamm etric peak current is in linear relation with the potential sweep rate at a low scan rate. Cyt showed a surface-controlled electrode process. The standard hete rogeneous electron transfer rate constant calculated via ac impedence sp ectrum is 7.529×10-4 cm/s. The adsorbed Cyt c could electrocatalyze the reduction of hydrogen peroxide. The relationship between the catalytic curre nt and H_2O_2 concentration exhibits a Michaelis-Menten kinetic mechanism for the electrocatalytic process and the constant Kapp_m value was f ound to be 1.21×10-3 mol/L. The cytochrome c adsorbed on L-Cys/Au S AMs exhibits a comparably high affinity for H_2O_2.
出处
《应用化学》
CAS
CSCD
北大核心
2005年第3期295-299,共5页
Chinese Journal of Applied Chemistry
基金
湖北省自然科学基金(2002AB047)
湖北省教育厅基金(2002A00018)资助项目
