Electrocatalysis of the hydrogen production by [Fe] hydrogenase from Desulfovibrio vulgaris Hildenborough

摘要

ydrogenases are enzymes which catalyze hydrogen production/consumption reaction.In this paper,the [Fe] hydrogenase from Desulfovibrio vulgaris Hildenborough is shown to catalyze the direct hydrogen production from protons,int he absence of any promoter,at a basal pyrolytic graphite electrode using cyclic voltammetry techniques.The effect of several parameters upon catalytic current is investigated:pH,hydrogenase concentrationionic strength,competition with another protein (bovine serum albumin),cycling repetition,mode of electrode polishing.The extent and efficiency of the hydrogenase electroactivity are examined in thepresence of either an artificial electron carrier (methylviologen) or a physiological partner cytochrome C_3 isolated from the same bacterial strain.Results suggest that the electorn-transfer process is essentially controlled by a complex between both hydrogenase and cytochrome C_3.Electrocatalysis apears to ve largely govened by the adsorptionof hydorgenase on the electrode surface very linkely involving hydrophobic interactions.