Carbonic anhydrase inhibitors. Inhibition of mitochondrial isozyme V with aromatic and heterocyclis sulfonamides.

In addition to sulfonamides, metal complexing anions represent the second class of inhibitors of the zinc enzyme carbonic anhydrase (CA, EC 4.2. 1.1). The first inhibition study of the mitochondrial isozyme CA V (of murine and human origin) with anions is reported here. Inhibition data of the cytosolic isozymes CA I and CA II as well as the membrane-bound isozyme CA IV with a large number of anionic species such as halides, pseudohalides, bicarbonate, nitrate, hydrosulfide, arsenate, sulfamate, and sulfamidate and so on, are also provided for comparison. Isozyme V has an inhibition profile by anions completely different to those of CA I and IV. but similar to that of hCA II, which may have interesting physiological consequences. Similarly to hCA 11, the mitochondrial isozymes show micro-nanomolar affinity for sulfonamides such as sulfanilamide and acetazolamide.