CARBONIC ANHYDRASE INHIBITORY ACTIVITIES OF NOVEL PROTON TRANSFER SALTS AND THEIR Cu(II) COMPLEXES

In this study, two new proton transfer salts of sulfonamide derivatives of maleic acid, namely (ClHabt)+(mabsmal)- (1) and (ClHabt)+(pabsmal)- (2), were obtained from 2-amino-6-chlorobenzo-thiazole (Clabt) and N-(3-sulfamoylphenyl)maleamide acid (Hmabsmal) and N-(4-sulfamoyl-phenyl)maleamide acid (Hpabsmal), respectively. Also, the Cu(II) complexes (3 and 4) of salts (1 and 2) and of Hmabsmal (5) were prepared. Compounds 1-5 were characterized by elemental, NMR (1H and 13C), FTIR, and thermal analyses, as well as UV-Vis, magnetic moment, and molar conductivity meas-urements. Carbonic anhydrase isoenzymes (hCA I and II) were purified from human erythrocyte cells by affinity chromatography. The effects of the synthesized compounds on the hydratase and esterase activi-ties of CA isoenzymes were studied in vitro. The results reveal that the synthesized compounds inhibit both esterase and hydratase activities of hCA I and hCA II. The inhibition constants of the compounds (Ki) were determined according to the esterase activity measurements. Ki values of 1-5 are in the range of 0.06 +/- 0.003 mu M and 4.25 +/- 0.100 mu M for hCA I, and of 0.02 +/- 0.001 mu M and 3.21 +/- 0.200 mu M for hCA II.

Automated summary

Two new proton transfer salts and their Cu(II) complexes were synthesized. The compounds were characterized by various analytical techniques. Esterase and hydratase activities of carbonic anhydrase isoenzymes were studied in the presence of the synthesized compounds. The results showed that the compounds inhibited both esterase and hydratase activities of the isoenzymes.