The membrane carbonic anhydrases: from CO2 transport to tumor markers.

Abstract

The growing carbonic anhydrase family includes at least 11 enzymatically active isozymes (CAs) and several carbonic anhydrase-related proteins (CARPs) (Sly and Hu, 1995; Hewett-Emmett and Tashian, 1996). CAs I, II III, and VII are cytosolic isozymes covered extensively elsewhere in this volume. CA V is a mitochondrial isozyme expressed in the mitochondrial matrix (Dodgson et al., 1980It is thought to play a role in ureagenesis, providing HCO – 3 for carbamoyl phosphate synthase, and in gluconeogenesis, providing HCO –3 for pyruvate carboxylase (Dodgson and Cherian, 1989; Dodgson et al., 1993). There is emerging evidence for a second mitochondrial enzyme which has not yet been characterized. CA VI is the isozyme expressed in saliva (Murakami and Sly, 1987; Feldstein and Silverman, 1984; Fernley et al., 1989) that has been suggested to protect gastroesophageal mucosa from acid injury (Parkkila et al., 1997). The three known non-enzymatic CA-RPs CA VII, CA X, and CA XI are covered elsewhere in this volume. The focus of this report is on CA IV, CA IX, and CA XII, the three membrane CAs which were discovered in that order.KeywordsCarbonic AnhydraseHuman Carbonic AnhydraseCrab GillHuman Male Reproductive TractThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.