Mammalian carbonic anhydrase isozymes: evidence for a third locus.

Starch gel electrophoretic patterns of carbonic anhydrase (CA) isozymes were examined from tissue extracts of sheep, mice, rabbits, and chickens. In addition to the widely distributed and extensively studied B and C isozymes, an additional isozyme (called CA-A) was observed, which was predominantly localized in muscle tissue. Immunochemical studies showed the A isozyme to be homologous with CA-B. Developmental and tissue distribution analyses suggested that a third locus (A) is involved in carbonic anhydrase synthesis in mammals.