Kinetics of Inhibition by Acetazolamide and Sulfanilamide of Bicarbonate Dehydration Catalyzed by Bovine Carbonic Anhydrase. ∗

Summary

The 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.