The function of Ensembl gene identifier ENSG00000104267 (CA2, carbonic anhydrase 2) is as follows. Catalyzes the reversible hydration of carbon dioxide (PubMed:11327835, PubMed:11802772, PubMed:11831900, PubMed:12056894, PubMed:12171926, PubMed:1336460, PubMed:14736236, PubMed:15300855, PubMed:15453828, PubMed:15667203, PubMed:15865431, PubMed:16106378, PubMed:16214338, PubMed:16290146, PubMed:16686544, PubMed:16759856, PubMed:16807956, PubMed:17127057, PubMed:17251017, PubMed:17314045, PubMed:17330962, PubMed:17346964, PubMed:17540563, PubMed:17588751, PubMed:17705204, PubMed:18024029, PubMed:18162396, PubMed:18266323, PubMed:18374572, PubMed:18481843, PubMed:18618712, PubMed:18640037, PubMed:18942852, PubMed:1909891, PubMed:1910042, PubMed:19170619, PubMed:19186056, PubMed:19206230, PubMed:19520834, PubMed:19778001, PubMed:7761440, PubMed:7901850, PubMed:8218160, PubMed:8262987, PubMed:8399159, PubMed:8451242, PubMed:8485129, PubMed:8639494, PubMed:9265618, PubMed:9398308). Can also hydrate cyanamide to urea (PubMed:10550681, PubMed:11015219). Stimulates the chloride-bicarbonate exchange activity of SLC26A6 (PubMed:15990874). Essential for bone resorption and osteoclast differentiation (PubMed:15300855). Involved in the regulation of fluid secretion into the anterior chamber of the eye. Contributes to intracellular pH regulation in the duodenal upper villous epithelium during proton-coupled peptide absorption. {ECO:0000269|PubMed:10550681, ECO:0000269|PubMed:11015219, ECO:0000269|PubMed:11327835, ECO:0000269|PubMed:11802772, ECO:0000269|PubMed:11831900, ECO:0000269|PubMed:12056894, ECO:0000269|PubMed:12171926, ECO:0000269|PubMed:1336460, ECO:0000269|PubMed:14736236, ECO:0000269|PubMed:15300855, ECO:0000269|PubMed:15453828, ECO:0000269|PubMed:15667203, ECO:0000269|PubMed:15865431, ECO:0000269|PubMed:15990874, ECO:0000269|PubMed:16106378, ECO:0000269|PubMed:16214338, ECO:0000269|PubMed:16290146, ECO:0000269|PubMed:16686544, ECO:0000269|PubMed:16759856, ECO:0000269|PubMed:16807956, ECO:0000269|PubMed:17127057, ECO:0000269|PubMed:17251017, ECO:0000269|PubMed:17314045, ECO:0000269|PubMed:17330962, ECO:0000269|PubMed:17346964, ECO:0000269|PubMed:17540563, ECO:0000269|PubMed:17588751, ECO:0000269|PubMed:17705204, ECO:0000269|PubMed:18024029, ECO:0000269|PubMed:18162396, ECO:0000269|PubMed:18266323, ECO:0000269|PubMed:18374572, ECO:0000269|PubMed:18481843, ECO:0000269|PubMed:18618712, ECO:0000269|PubMed:18640037, ECO:0000269|PubMed:18942852, ECO:0000269|PubMed:1909891, ECO:0000269|PubMed:1910042, ECO:0000269|PubMed:19170619, ECO:0000269|PubMed:19186056, ECO:0000269|PubMed:19206230, ECO:0000269|PubMed:19520834, ECO:0000269|PubMed:19778001, ECO:0000269|PubMed:7761440, ECO:0000269|PubMed:7901850, ECO:0000269|PubMed:8218160, ECO:0000269|PubMed:8262987, ECO:0000269|PubMed:8399159, ECO:0000269|PubMed:8451242, ECO:0000269|PubMed:8485129, ECO:0000269|PubMed:8639494, ECO:0000269|PubMed:9265618, ECO:0000269|PubMed:9398308}.