Voltammetric investigation of cytochrome c on gold coated with a self-assembled glutathione monolayer

The direct, reversible electrochemistry of horse-heart cytochrome c (cyt. c) was realized on a self-assembled glutathione (GSH) monolayer modified Au electrode. The voltammetric responses of cyt. c on GSH/Au electrode were found to be affected by pH during the electrode modification, metal ions and surfactants. Using potassium ferricyanide [K4Fe(CN)6] as a probe, these effects on the voltammetric responses of cyt. c were characterized by electrochemical methods. It was found that the pH during the electrode modification, metallic ions and surfactants changed GSH monolayer's charge state and the conformation on the electrode surface, and resulted in the influence on the voltammetric responses of cyt. c. The experimental results provided us information to understand the mechanism of the interfacial electron transfer of electrode-protein, as well as the electron transfer of cyt. c in life system.