Tritium NMR studies of the human carbonic anhydrase I-benzenesulfonamide complex

Tritium NMR spectroscopy has been used to examine the complex formed by [4-H-3]benzenesulfon-amide and human carbonic anhydrase I. The results show that in solution the inhibitor forms a 1:1 complex with the enzyme. A 100-spin computational model of the system, constructed with reference to crystallographic results, was used to interpret tritium relaxation behavior and H-3{H-1} NOEs. The analysis shows that the rate of dissociation of the enzyme-sulfonamide complex is 0.35 s(-1) and that the aromatic ring of the inhibitor undergoes rapid rotation while complexed.