¹⁹F nuclear magnetic resonance studies of the interaction of inhibitors with chymotrypsin. Ring-fluorinated derivatives of N-trifluoroacetylphenylalanine

Abstract

The complexes formed between chymotrypsin and the doubly fluorine- labelled inhibitors, o-, m- and p-fluoro-N-trifluoroacetyl-D- phenylalanine and 2,4-difluoro-N-trifluoroacetyl-D-phenylalanine, have been characterized by ¹⁹F N.M.R. spectroscopy and binding parameters, Δ_B and K_I, have been derived. The results confirm the importance of the amido binding site in orienting aromatic amino acids at the active site of chymotrypsin. Changes in Δ_B, the change in chemical shift of the enzyme-bound inhibitor, are shown to be a very sensitive probe of enzyme-inhibitor interactions.