High Quality Content by WIKIPEDIA articles! hydrogenase is a type of hydrogenase, which is an oxidative enzyme that reversibly activates molecular hydrogen in prokaryotes and some eukaryotes. The catalytic site on the enzyme provides simple hydrogen-metabolizing microorganisms a redox mechanism by which to store and utilize energy via the reaction shown in Figure 1. This is particularly essential for the anaerobic, sulfate-reducing bacteria of the genus Desulfovibrio. The practical application of this enzyme is a renewable, more environmentally friendly energy source.