Enables carbonate dehydratase activity. Involved in positive regulation of dipeptide transmembrane transport and regulation of intracellular pH. Acts upstream of or within several processes, including carbon dioxide transport; positive regulation of GABAergic synaptic transmission; and positive regulation of cellular pH reduction. Located in cytosol and myelin sheath. Is expressed in several structures, including alimentary system; brain; heart; metanephros; and sensory organ. Used to study autosomal recessive osteopetrosis 3. Human ortholog(s) of this gene implicated in autosomal recessive osteopetrosis 3 and osteopetrosis. Orthologous to human CA2 (carbonic anhydrase 2). [provided by Alliance of Genome Resources, Apr 2022]