Hydrogenase

The hydrogenases are enzymes that catalyze the reversible oxidation of molecular hydrogen :

${\displaystyle \mathrm {H_{2}\rightleftarrows H^{+}+H^{-}\rightleftarrows 2\ H^{+}+2\ e^{-}} }$

This reaction plays an important role in nitrogen fixation and in the methanogenesis of biomass to methane . Both anaerobic ( archaea / bacteria) and a few aerobic microorganisms ( bacteria , some algae ) contain hydrogenase enzymes. Hydrogen-consuming methanogens live syntrophically together with hydrogen-forming bacteria. It is estimated that around 150 million tons of hydrogen are produced annually by microorganisms.

The term "hydrogenase" was introduced in 1931 by the two researchers Marjory Stephenson and Leonard Hubert Stickland , who discovered the Stickland reaction . Understanding how they work and how they work can e.g. B. serve to improve hydrogen bioreactors .

Biochemical classification

EC  1.12.1.2 Hydrogen dehydrogenase (hydrogen: NAD ⁺ oxidoreductase )

H ₂ + NAD ⁺ = H ⁺ + NADH

EC  1.12.1.3 Hydrogen dehydrogenase ( NADP ) (hydrogen: NADP ⁺ oxidoreductase)

H ₂ + NADP ⁺ = H ⁺ + NADPH

EC  1.12.2.1 Cytochrome - c ₃ hydrogenase (hydrogen: ferricytochrome c ₃ oxidoreductase)

2H ₂ + ferricytochrome c ₃ = 4H ⁺ + ferrocytochrome c ₃

EC  1.12.7.2 Ferredoxin hydrogenase (hydrogen: ferredoxin oxidoreductase)

H ₂ + oxidized ferredoxin = 2H ⁺ + reduced ferredoxin

EC  1.12.98.1 Coenzyme F ₄₂₀ Hydrogenase (hydrogen: Coenzyme F ₄₂₀ -oxidoreductase)

H ₂ + coenzyme F ₄₂₀ = reduced coenzyme F ₄₂₀

EC  1.12.5.1 hydrogen: quinone oxidoreductase

H ₂ + menaquinone = menaquinol

EC  1.12.98.2 5,10-methenyltetrahydromethanopterin hydrogenase (hydrogen: 5,10-methenyltetrahydromethanopterin oxidoreductase)

H ₂ + 5,10-methenyl tetrahydromethanopterin = H ⁺ + 5,10-methylenetetrahydromethanopterin

EC  1.12.98.3 Methanosarcina phenazine hydrogenase [hydrogen: 2- (2,3-dihydropentaprenyloxy) phenazine oxidoreductase]

H ₂ + 2- (2,3-dihydropentaprenyloxy) phenazine = 2-dihydropentaprenyloxyphenazine

Structural classification

The current classification takes into account that different metals such as nickel or iron, either individually or jointly bound to sulfur (usually as a cluster) or not bound to sulfur, make up the catalytic center of hydrogenases.

literature

• Thauer, RK. et al . (2010): Hydrogenases from methanogenic archaea, nickel, a novel cofactor, and H2 storage . In: Annu Rev Biochem . 79; 507-536; PMID 20235826 ; doi : 10.1146 / annurev.biochem.030508.152103
• Tamagnini, P. et al . (2007): Cyanobacterial hydrogenases: diversity, regulation and applications . In: FEMS Microbiol Rev . 31 (6); 692-720. PMID 17903205 ; doi : 10.1111 / j.1574-6976.2007.00085.x .
• Vignais, PM. and Colbeau, A. (2004): Molecular biology of microbial hydrogenases . In: Curr Issues Mol Biol . 6 (2); 159-188; PMID 15119826 ; PDF (free full text access)

Individual evidence

1. ↑ Thauer, RK. et al . (2010): Hydrogenases from methanogenic archaea, nickel, a novel cofactor, and H2 storage . In: Annu Rev Biochem . 79; 507-536; PMID 20235826 ; doi : 10.1146 / annurev.biochem.030508.152103
2. ↑ Stephenson, M. and Stickland, LH. (1931): Hydrogenase: a bacterial enzyme activating molecular hydrogen: The properties of the enzyme . In: Biochem J . Volume 25, Number 1, 1931, pp. 205-214, PMID 16744569 , PMC 1260629 (free full text).