Drug-biomolecule interactions: topographical study of active site of erythrocyte carbonic anhydrase using spin-labeled sulfanilamide drugs.

The topography of the active sites of human erythrocyte carbonic anhydrases B and C and bovine erythrocyte carbonic anhydrase B was studied using a series of spin-labeled sulfanilamide analogs. Results show that the active site of human carbonic anhydrase C is a narrow cleft approximately 14 A in depth. This observation is in good agreement with previously published X-ray diffraction data. While the active sites of human carbonic anhydrase B and bovine carbonic anhydrase B have the same general shape as the active site of human carbonic anhydrase C, they are slightly deeper.