Figure 4.

Carbonic anhydrases (CAs) as possible molecular targets in cancer treatment (A) The family of the carbonic anhydrases comprise several members located either at the plasma membrane, in the cytosol or in the mitochondria. Among these pH regulators, CA9 and CA12 seem to have an important role in cancer, where they are usually overexpressed (B) Mechanism of action of sulphonamides in CA inhibition. CAs need a zinc residue bound to three histidines for the catalytic reaction. Sulphonamides bind to this zinc atom and displaces a molecule of water that is needed for the transformation of CO₂ into NCO₃^–.