Direct electrochemistry of cytochrome c entrapped in agarose hydrogel by protein film voltammetry

Cytochrome c (cyt-c) entrapped in agarose hydrogel was electrostatically bound to the edge plane pyrolytic graphite electrode (EPPGE), and then stable agarose-cyt-c/EPPGE was prepared. Direct electrochemistry between cyt-c and the EPPGE was monitored by protein film voltammetry. The effects of ionic strength, pH and exterior substances on the direct electrochemistry, and electrocatalytic properties of cyt-c were also studied. Results show that the electrochemical behavior of heme Fe(III)/Fe(II) in cyt-c is quasireversible. Its electrochemical performance is the best when the concentration of supporting electrolyte phosphate buffer solution is 0.2 mol/l and pH is 7.0, and greatly inhibited by exterior metal ions. Catalytic reduction of oxygen could also be achieved at the agarose-cyt-c/EPPGE.