Factors influencing the electron-transfer rates of redox proteins

Abstract

The electron-transfer reaction of cytochrome c at a surface-modified gold electrode has been investigated using a variety of electrochemical techniques. The reaction is rapid and the mechanism, deduced from the observed electrode kinetics, involves adsorption of the protein at the electrode surface prior to electron transfer. This adsorption step is a crucial factor in the enhancement of the observed, overall rate of the electron-transfer reaction, for which there is a large free energy of activation for the electron-transfer step itself. The relationship between the heterogeneous electron-transfer reaction of cytochrome c and its reaction with its physiological redox partners in homogeneous solution is discussed.