Mitochondrial carbonic anhydrase that catalyzes the reversible conversion of carbon dioxide to bicarbonate/HCO3 (PubMed:8356065, PubMed:24530203). Mitochondria are impermeable to HCO3, and thus this intramitochondrial carbonic anhydrase is pivotal in providing HCO3 for multiple mitochondrial enzymes that catalyze the formation of essential metabolites of intermediary metabolism in the urea and Krebs cycles (PubMed:24530203). H(+) + hydrogencarbonate = CO2 + H2O Activated by L- and D-histidine (PubMed:16807956). Activated by L- and D-phenylalanine (PubMed:16686544). Activated by L-adrenaline (PubMed:17127057). Inhibited by coumarins, sulfonamide derivatives such as acetazolamide and Foscarnet (phosphonoformate trisodium salt) (PubMed:17314045, PubMed:19186056, PubMed:19206230, PubMed:18618712). Activated by histamine (PubMed:17127057). The disease is caused by variants affecting the gene represented in this entry. Belongs to the alpha-carbonic anhydrase family.