The carbonic anhydrases form a family of enzymes that catalyze the interconversion between carbon dioxide and water and the dissociated ions of carbonic acid. The active site of most carbonic anhydrases contains a zinc ion.
The bivalent form of zinc (Zn+2) is a constituent of enzymes like carbonic anhydrase, hexokinase, alcohol dehydrogenase, lactic dehydrogenase and carboxypeptidase.