In vitro investigation of the effects of 4-sulfamoylbenzoic acid metal complexes on human carbonic anhydrases hCA I and hCA II

Carbonic anhydrases (CAs) are metalloenzymes with high catalytic activity and specificity that catalyze the reversible conversion of CO2 to bicarbonate and a proton. In mammals, CA isoenzymes are involved in numerous vital processes, primarily including respiration, acid-base balance, and ion transport. From the perspective of clinical biochemistry and pharmacology, the most extensively studied isoforms, hCA I and hCA II, are notable for their expression profiles in different tissues and their sensitivity to inhibitors. In this context, the selective inhibition of CA isoenzymes offers therapeutic potential for the treatment of various diseases, particularly glaucoma and epilepsy. In this study, human erythrocyte hCA I and hCA II isoenzymes were successfully purified using a p-aminobenzonesulfonamide affinity gel that covalently bonded onto CNBr-Sepharose®4B matrix. The hCA I isoenzyme was purified with a yield of 21.81%, and hCA II with a yield of 24.95%, and their specific activities were determined as 1133.64 and 2106.89 EU/mg protein, respectively. Qualitative protein determination was carried out spectrophotometrically, and quantitative protein determination was carried out by the Folin-Lowry method. The purity of the enzymes was checked by SDS-PAGE analysis. The inhibition potentials of seven 4-sulfamoylbenzoic acid metal complexes synthesized within the scope of the study on hCA I and hCA II were tested by esterase activity method, and IC50 and Ki values of the inhibitor compounds were calculated. It was determined that the synthesized compounds had inhibitory effects comparable to the reference compound AAZ.