Voltammetric Behavior of Cytochromes c₂ and c' from Rhodospirillum rubrum at an ITO Electrode

Abstract

The direct electrochemical redox behavior of Rhodospirillum rubrum cytochromes c₂ and c' could be observed at an ITO electrode pretreated with a few surfactants or with 1 M HNO₃. Well-defined redox waves were observed on the voltammograms with + 310 mV of formal redox potential for cyt. c₂ and −15 mV for cyt. c', corresponding to a quasi-reversible one-electron system. The reversible redox reaction of cytochrome c₂ could be observed at a moderately hydrophilic ITO surface, while the highly hydrophilic surface was necessary for cytochrome c'.