Fig. 1.

Structures of the two arylsulfonamides and schematics of the three biophysical techniques used in this analysis. The interactions of either (A) 4-carboxybenzenesulfonamide (CBS) or (B) dansylamide (DNSA), with carbonic anhydrase II (CA II), were analyzed by (C) surface plasmon resonance (SPR), (D) isothermal titration calorimetry (ITC), and (E) stopped-flow fluorescence (SFF). In each assay, the compounds are denoted as circles and the protein is indicated as a black shape. In the ITC study of the CA II/DNSA interaction, however, the orientation of the assay was reversed to accommodate the low aqueous solubility of DNSA.