Kinetics of inhibition by acetazolamide and sulfanilamide of bicarbonate dehydration catalyzed by bovine carbonic anhydrase.

Abstract

SummaryThe kinetics of inhibition by acetazolamide and sulfanilamide of the formation of carbon dioxide from bicarbonate, catalyzed by partially purified carbonic an-hydrase preparations from bovine erythrocytes, were those of competitive inhibition. This is contrasted with the non-competitive kinetics of sulfonamide inhibition of a number of carbonic anhydrase-mediated hydration reactions. K1 for acetazolamide was 8.6 × 10-8 M while that for sulfanilamide was 1.8 × 10-5 M; these values are similar to those reported for inhibition of CO2 hydration in the presence of bovine erythrocyte enzyme.Note added in proof. From other types of evidence, J. E. Coleman (personal communication) has written a reaction scheme similar to that presented here.