InterPro domain: IPR045066

Carbonic anhydrases (CA) are zinc-containing enzymes that catalyse the reversible hydration of carbon dioxide in a two-step mechanism in which the nucleophilic attack of a zinc-bound hydroxide ion on carbon dioxide is followed by the regeneration of an active site by ionization of the zinc-bound water molecule and removal of a proton from the active site. CAs are ubiquitous enzymes involved in fundamental processes like photosynthesis, respiration, pH homeostasis and ion transport. There are three evolutionarily distinct families of CAs (the alpha-, beta-, and gamma-CAs) which show no significant sequence identity or structural similarity. Within the beta-CA family there are four evolutionarily distinct clades (A through D) [ 1 ].This entry represents the cladeB of the beta-CA family. Proteins in this entry are mostly from plants and bacteria, including BCA1-6 from Arabidopsis and CynT from E. coli. BCA1 and BCA4 have been shown to acts as upstream regulators of CO2-controlled stomatal movements in guard cells [ 2 ]. CynT catalyses the hydration of carbon dioxide and thus prevents depletion of cellular bicarbonate [ 3 ].

1. Carbonic anhydrase: new insights for an ancient enzyme. J. Biol. Chem. 276, 48615-8
2. Carbonic anhydrases are upstream regulators of CO2-controlled stomatal movements in guard cells. Nat Cell Biol 12, 87-93; sup pp 1-18
3. Carbonic anhydrase in Escherichia coli. A product of the cyn operon. J. Biol. Chem. 267, 3731-4