STABLE AND REVERSIBLE ELECTROCHEMISTRY OF CYTOCHROME-C ON BARE ELECTRODES .1. EFFECT OF IONIC-STRENGTH

Stable and reversible electrochemical responses of cytochrome c can be measured on bare unmodified gold and glassy carbon electrodes. It has been found that in phosphate buffers the electrochemical behaviour va ries from completely irreversible to reversible on both electrodes dep ending on the concentration of the supporting electrolyte. The optimum phosphate concentration was found to be between 20 and 30 mM. It was also observed that the electrochemical response improved with the life time of the protein samples and could be destroyed by mechanical aggre gation of cytochrome c molecules. The importance of oligomeric forms o f cytochrome c on the electrode surfaces was emphasized; they determin e the overall electrochemical behaviour.