Electrochemically Different Behaviors of Cytochrome c in the Presence of Organic Phosphates

The electrochemical effects of adenosine triphosphate (ATP), guanosine 3ʹ,5ʹ- tetraphosphate (GTP), guanosine diphosphate (GDP) and guanosine monophosphate (GMP), on the cytochrome c, were investigated with the iodide modified silver electrode in 0.01 M KNO3 at pH 7.0. Anodic and cathodic peaks were observed at 550 and 94 mV vs. Ag/AgCl, and the formal potential was calculated to be 322 mV vs. Ag/AgCl. The effects of ATP, GTP, GDP and GMP concentrations were determined on the anaerobic redox reaction. ATP led to a positive shift in the anodic and cathodic peaks of cytochrome c (Cyt c) to 599 and 141 mV, respectively. These shifts caused a facilitated-reduction reaction whilst the oxidation one became harder in the presence of ATP. GTP caused a positive shift in the cathodic peak up to 152 mV and a negative shift in the anodic peak to 495 mV, resulting in facilitated oxidation and reduction reactions of Cyt c. GDP decreased the anodic and cathodic peak currents without changing their potentials, whilst GMP did not affect the cathodic and anodic peaks of Cyt c, indicating the lack of affinity of Cyt c for this material.