Various Carbonic Anhydrases in Physiopathological Events, Carbonic Anhydrase Inhibitors, and Hybrid Compounds

Enzymes are highly specific catalysts that accelerate reactions in biological systems. Carbonic anhydrase (CA) is an enzyme found in plants, microorganisms, and vertebrates. CA catalyses CO2 hydration/ dehydration. There are different families and isoenzymes of CAs. Fifteen α-CA isoenzymes have been reported in humans. The status of CO2 hydration and dehydration is important for a variety of biological processes. CAs play an important role in many physiological and pathological events in several tissue types. Their levels are increased in some diseases; therefore, CA inhibition has been applied as a therapeutic option. However, the high diversity of these isoenzymes is an important consideration. Isoenzyme- specific CA inhibitors can reduce the side effects of treatment. Some agents containing additional sulfonamides approved for other therapeutic applications, such as topiramate, celecoxib/valdecoxib, sulpiride, and famotidine, have inhibitory effects on CA isoenzymes. These bind to the zinc ion in the CA active site. Recently, research has been conducted on the use of a hybrid form of active ingredient and a CA inhibitor. CA inhibitor-NSAID hybrid compounds demonstrated more efficacy than NSAIDs in arthritis, which has attracted further attention of researchers in conducting research on CA-hybrid drugs.