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

Tritium NMR spectroscopy has been used to examine the complex formed by [4-³H]benzenesulfon-amide and human carbonicanhydrase I. The results show that in solution the inhibitor forms a 1:1complex 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 ³H{¹H}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