Carbonic Anhydrase X (CA10) belongs to CA family of zinc metalloenzymes, which catalyze the reversible hydration of carbon dioxide in various biological processes such as respiration, renal tubular acidification and bone resorption. While CA10 is a secreted protein without Carbonic Anhydrase activity (i.e., the reversible hydration of CO2) due to point mutations in the zinc binding site, it has esterase activity. The human and mouse CA10 are expressed in the brain, indicating that they may play a role in brain development.