CARBONIC-ANHYDRASE ACTIVATORS - PART 17 - SYNTHESIS AND ACTIVATION STUDY OF A SERIES OF RIAZOLE-(1H)-3-YL)-2,4,6-TRISUBSTITUTED-PYRIDINIUM SALTS AGAINST ISOZYME-I, ISOZYME-II AND ISOZYME-IV

A series of pyridinium salts were prepared by reaction of 3-amino-(1H) -1,2,4-triazole with 2,4,6-trisubatituted pyrylium salts. The new comp ounds have been characterized by standard procedures and were assayed for their interaction with three carbonic anhydrase (CA) isozymes, the cytosolic CA I and CA II, as well as the membrane-bound CA IV. The py ridinium salts activate the three isozymes in a different manner, with CA IV being the most susceptible to activation, followed by CA I, whe reas CA II is the least sensitive to this class of activators. Compoun ds possessing 2,6-dialkyl-4-phenyl substituents at the pyridinium ring were the most effective activators. This is the first study of compar ative activation for several CA isozymes, proving that activators, sim ilarly to inhibitors possess isozyme-specificity.