Hydrogenase

A hydrogenase is an enzyme that catalyses the reversible oxidation of molecular hydrogen (H₂). Hydrogenases play a vital role in anaerobic metabolism.

Hydrogen uptake (H₂ oxidation) (1) is coupled to the reduction of electron acceptors such as oxygen, nitrate, sulfate, carbon dioxide, and fumarate, whereas proton reduction (H₂ evolution) (2) is essential in pyruvate fermentation and in the disposal of excess electrons. Both low-molecular weight compounds and proteins such as ferredoxins, cytochrome c₃, and cytochrome c₆ can act as physiological electron donors (D) or acceptors (A) for hydrogenases:

H₂ + A_ox → 2H+ + A_red (1)

2H+ + D_red → H₂ + D_ox (2)

Hydrogenases were first discovered in the 1930s, and they have since attracted interest from many researchers including inorganic chemists who have synthesized a variety of hydrogenase mimics. Understanding the catalytic mechanism of hydrogenase might help scientists design clean biological energy sources, such as algae, that produce hydrogen..