Carbonic Anhydrase 13 (CA13) belongs to the carbonic anhydrase family which can catalyzes the reversible hydration recation of carbon dioxide. Carbonic anhydrases participate in many biological processes, including respiration, calcification, acid-base balance, bone resorption, and the formation of aqueous humor, cerebrospinal fluid, saliva, and gastric acid. CA13 is a cytosolic enzyme and is widely expressed in human, such as thymus, small intestine, spleen, prostate, ovary, colon and testis, indicating that it may play a key role in several organs. CA13 is inhibited by acetazolamide.