Meta-Biol

• Pathways

Carbonic anhydrase VI (CA6) hydrates carbon dioxide to yield bicarbonate and a proton (Thatcher et al. 1998, Nishimori et al. 2007).Carbonic anhydrase deprotonates water to yield a zinc-hydroxyl group and a proton which is transferred to external buffer molecules via histidine or glutamate residues in carbonic anhydrase. The hydroxyl group reacts with carbon dioxide in the active site to yield bicarbonate. A water molecule displaces the bicarbonate and the reaction cycle begins again (reviewed in Lindskog 1997). Depending on the concentrations of reactants the reaction is reversible. CA6 is a major protein of saliva and is also known as gustin.