¹⁹F nuclear magnetic resonance studies of the interaction of inhibitors with chymotrypsin. N-Acetyl derivatives of fluorophenylalanines

Abstract

Binding parameters, Δ_B and K_I, for the three competitive inhibitors N- acetyl-o-fluoro-D-phenyl-alanine, N-acetyl-m-fluoro-D-phenylalanine and N-acetyl-p-fluoro-D-phenylalanine have been determined by Fourier- transform ¹⁹F n.m.r, techniques. Association between the enzyme aromatic binding site and the three inhibitors appears to result in greater immobilization of the aromatic rings than is the case for the analogous N-trifluoroacetyl compounds. A balance between the enzyme-inhibitor interactions at the aromatic and amido binding sites is believed to be responsible for the observed effects. The relationship between K_I and K_S values of inhibitors obtained from kinetic data and K_I values obtained by N.M.R. methods is discussed.