What is Hydrogenase?

A hydrogenase is an enzyme that catalyses the reversible oxidation of molecular hydrogen , as shown below:

Hydrogen uptake is coupled to the reduction of electron acceptors such as oxygen, nitrate, sulfate, carbon dioxide , and fumarate. On the other hand, proton reduction is coupled to the oxidation of electron donors such as ferredoxin , and serves to dispose excess electrons in cells. Both low-molecular weight compounds and proteins such as FNRs, cytochrome c3, and cytochrome c6 can act as physiological electron donors or acceptors for hydrogenases.