Anti-Car4 antibodies are protein reagents that detect specific antigens. The Car4 antigen is another term for the human protein carbonic anhydrase 4, encoded by the CA4 gene. The protein is known to catalyze the reversible hydration of carbon dioxide into bicarbonate and protons and thus is essential to maintaining intracellular and extracellular pH. Canonically, it has an amino acid length of 312 residues and a mass of 35 kilodaltons. Its subcellular localization is in the cell membrane and it is reported to be expressed in the endothelium of the choriocapillaris in eyes. The Car4 protein is a member of the Alpha-carbonic anhydrase protein family. Other alias names for Car4 include CAIV and RP17. A number of Car4 antibodies have been mentioned in research publications and have associated citations. Western Blot is a widely used application for these antibodies. ELISA and Immunohistochemistry are also common applications.