Hydrogenase

A hydrogenase is an enzyme that catalyses the reversible oxidation of molecular hydrogen (H₂), as shown below:

H₂ + A_ox → 2H⁺ + A_red

(1)

2H⁺ + D_red → H₂ + D_ox

(2)

Hydrogen uptake (1) is coupled to the reduction of electron acceptors such as oxygen, nitrate, sulfate, carbon dioxide (CO₂), and fumarate. On the other hand, proton reduction (2) is coupled to the oxidation of electron donors such as ferredoxin (FNR), and serves to dispose excess electrons in cells (essential in pyruvate fermentation). 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.^[1]

^ Vignais PM, Billoud B, Meyer J (August 2001). "Classification and phylogeny of hydrogenases". FEMS Microbiology Reviews. 25 (4): 455–501. doi:10.1111/j.1574-6976.2001.tb00587.x. PMID 11524134.

[1] Vignais PM, Billoud B, Meyer J (August 2001). "Classification and phylogeny of hydrogenases". FEMS Microbiology Reviews. 25 (4): 455–501. doi:10.1111/j.1574-6976.2001.tb00587.x. PMID 11524134.

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