Electrocatalysis at hydrogenase or cytochrorme C3‐modified glassy carbon electrodes

The immobilization of two redox proteins, hydrogenase and cytochrome c3 extracted from Desulfovibrio desulfurifcans sulfate‐reducing bacterium, on glassy carbon electrodes modified via carbodiimide procedure is reported. The catalytic activity at the hydrogenase‐modified glassy carbon electrode is detected in the presence of methylviologen, which acts as a shuttle between immobilized hydrogenase and the electrode surface. The effect of experimental parameters (e.g., methylviologen concentration or pH) on the catalytic activity is examined; maximum activity is observed at pH 9.5. Catalytic activity is also detected when methylviologen is replaced by cytochrome c3, which is the physiological partner of hydrogenase. The cytochrome C3‐modified glassy carbon does not yield a stable electrochemical response due to cytochrome c3 reconformation at the electrode surface.