Enzyme involved in the catabolism of H(2)CO(3) but that does not mediates the reversible hydration of carbon dioxide. Mediates complex I assembly in mitochondria and respiration (By similarity). Homotrimer. Component of the mitochondrial oxidoreductase respiratory chain complex I; element of the extra matrix-exposed domain, which is attached to the membrane arm of this complex (Probable). Probably integral to the membrane. A number of isoforms are produced. According to EST sequences. Belongs to the gamma-class carbonic anhydrase family.