Interaction between the basic inhibitor of bovine pancreas and chymotrypsin and trypsin. Selective anthraniloylation of the maleylated inhibitor

The interaction between the maleylated basic pancreatic inhibitor, anthraniloylated on its lysine-15 residue, and chymotrypsin is studied by fluorescence intensity, fluorescence polarization, circular dichroism, circular polarization of fluorescence and sedimentation. These measurements show that the interaction takes place through the entrance of the anthraniloyl group into an asymmetric environment in which it is rigidly held. The dissociation constant of the complex is 2.5 × 10^?8m. The interaction between the modified inhibitor and trypsin takes place through a site which is not the anthraniloylated lysine-15 side-chain, yet not far from it.