Carbonic anhydrases (CAs) are members of a large family of zinc metalloenzymes that catalyze the reversible hydration of carbon dioxide. CAs are involved in a variety of biological processes, including respiration, calcification, acid-base balance, bone resorption, and the formation of aqueous humor, cerebrospinal fluid, saliva, and gastric juice. They show extensive diversity in distribution and in their subcellular localization. The human CA5A gene encodes for the CA V protein which is expressed in the mitochondrial matrix in liver tissues, but can also be detected in many other tissues. In ureagenesis, the CA V protein may be involved in providing bicarbonate to carbamoyl phosphate synthetase.