Carbonic anhydrase 1 is a zinc metalloenzyme that catalyses reversible hydration of CO2(CO2 + H2O ? HCO3- + H+). Carbonic anhydrase 1 is essential to many biological processes such as cellular respiration, calcification, acid-base balance, bone resorption, and the formation of aqueous humor, cerebrospinal fluid, salvia, and gastric acid. Carbonic anhydrase 1 is abundant in erythrocytes and an early marker for erythroid differentiation.