Drug protein interaction at the molecular level: A study of sulphonamide carbonic anhydrase complexes.

The molecular mechanism of drug action has been studied by X-ray diffraction analysis of human carbonic anhydrase I complexed with two different sulphonamides. The acetazolamide and amino benzene sulphonamide are found to bind to the catalytically essential zinc ion thereby inhibiting the function of the enzyme. The inhibitor molecules are stabilized in the active site of the protein by van der Waals interaction with a number of protein side chain groups.