Inhibition Studies of Three Classes of Desulfovibrio Hydrogenase: Application to the Further Characterization of the Multiple Hydrogenases Found in Desulfovibrio Vulgaris Hildenborough

The three types of hydrogenase hitherto characterized in genus Desulfovibrio exhibit distinctive inhibition patterns of their proton-deuterium exchange activity by CO, NO and NO2−. The (Fe) and (NiFeSe) hydrogenases are the most sensitive to all three inhibitors while the (NiFe) enzymes, relatively little inhibited by CO, are still very sensitive to NO but unaffected by NO2−. These differences together with some specific catalytic properties, in particular the pH profile and the H2 to HD ratio in the exchange reaction, constitute a simple means of characterizing multiple hydrogenases present in one or different species.