Thermodynamic and kinetic aspects of the electron transfer reaction of bovine cytochrome c immobilized on 4-mercaptopyridine and 11-mercapto-1-undecanoic acid films

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• 作者：Stefano Monari ; Gianantonio Battistuzzi ; Marco Borsari ; Diego Millo ; Cees Gooijer ; Gert van der Zwan ; Antonio Ranieri and Marco Sola
• 关键词：Electron transfer ; Bovine cytochrome c ; Redox potential ; Cyclic voltammetry ; Surface immobilization ; Self assembled monolayers
• 刊名：Journal of Applied Electrochemistry
• 出版年：2008
• 出版时间：July, 2008
• 年：2008
• 卷：38
• 期：7
• 页码：885-891
• 全文大小：365.0 KB

文摘

Bovine cytochrome c (cyt c) was adsorbed on a polycrystalline gold electrode coated with 4-mercaptopyridine and 11-mercapto-1-undecanoic acid self-assembled monolayers (SAMs) and the thermodynamics and kinetics of the heterogeneous protein-electrode electron transfer (ET) reaction were determined by cyclic voltammetry. The E¡ã′ values for the immobilized protein were found to be lower than those for the corresponding diffusing species. The thermodynamic parameters for protein reduction ( \Updelta H_rc ¡ã¡é \Updelta {H}_{{\rm rc}} ^{{\circ \prime }} and \UpdeltaS_rc¡ã¡é \Updelta{S}_{{\rm rc}}^{{\circ \prime }} ) indicate that the stabilization of the ferric state due to protein–SAM interaction is enthalpic in origin. The kinetic data suggest that a tunneling mechanism is involved in the ET reaction: the distance between the redox center of the protein and the electrode surface can be efficiently evaluated using the Marcus equation.