Carbonic anhydrase IX is a member of the carbonic anhydrase family. This family consists of catalytic enzymes capable of converting carbon dioxide and water into carbonic acid, protons, and bicarbonate ions. This family of molecules is abundantly expressed in all mammalian tissues and helps to govern the pH in normal tissues. CAIX is very stable and found in the membrane. It is also one of the most hypoxically-inducible genes, thus establishing its application as a reliable and consistent hypoxia histochemical marker.
