CA4:Zn2+ hydrates CO2 to HCO3-

Stable Identifier
Reaction [transition]
Homo sapiens
Carbonic anhydrase IV hydrates carbon dioxide to bicarbonate and a proton, H2O + CO2 -> H+ + HCO3-
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Carbonic anhydrase IV (CA4) anchored to extracellular face of the plasma membrane (Wistrand et al. 1999) hydrates carbon dioxide (CO2) to yield bicarbonate (HCO3-) and a proton (H+) (Zhu & Sly 1990, Okayuma et al. 1992, Baird et al. 1997, Innocenti et al. 2004). During the reaction a hydroxyl group bound by the zinc ion (Zn2+) of CA4 attacks the CO2 molecule to directly form HCO3- (reviewed in Lindskog 1997). The HCO3- is displaced by water, which is then deprotonated by a histidine residue to recreate the Zn2+:hydroxyl group. Depending on the concentrations of reactants the reaction is reversible.

Literature References
PubMed ID Title Journal Year
9054574 Catalysis and inhibition of human carbonic anhydrase IV

Sly, WS, Fierke, CA, Okuyama, T, Baird TT, Jr, Waheed, A

Biochemistry 1997
2111324 Carbonic anhydrase IV from human lung. Purification, characterization, and comparison with membrane carbonic anhydrase from human kidney

Sly, WS, Zhu, XL

J Biol Chem 1990
15501038 Carbonic anhydrase inhibitors: inhibition of the membrane-bound human isozyme IV with anions

Innocenti, A, Wurl, M, Supuran, CT, Scozzafava, A, Antel, J, Firnges, MA

Bioorg Med Chem Lett 2004
1311094 Human carbonic anhydrase IV: cDNA cloning, sequence comparison, and expression in COS cell membranes

Sly, WS, Sato, S, Okuyama, T, Waheed, A, Zhu, XL

Proc Natl Acad Sci U S A 1992
10090333 Carbonic anhydrase IV activity is localized on the exterior surface of human erythrocytes

Carter, ND, Wistrand, PJ, Conroy, CW, Mahieu, I

Acta Physiol Scand 1999
9336012 Structure and mechanism of carbonic anhydrase

Lindskog, S

Pharmacol Ther 1997
Catalyst Activity

carbonate dehydratase activity of CA4:Zn2+ [plasma membrane]

Orthologous Events
Cross References
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