On the complex formation between basic pancreatic trypsin inhibitor and TLCK-, TPCK-derivatives of beta-trypsin

The study of the interaction of the pancreatic inhibitor with different alkylated derivatives of alpha- and beta-trypsin shows that: 1) TLCK-beta-trypsin forms a complex with pancreatic inhibitor in tris buffer and tris-ethanol 40% system. 2) TLCK-alpha-trypsin and TLCK-TPCK-beta-trypsin have lost their ability to complex formation with pancreatic inhibitor. TLCK-alpha-trypsin and TLCK-TPCK-beta-trypsin are in derivatives in which the "chymotryptic" active site is destroyed. The results presented in this paper prove the participation of the "chymotrypic" active site in the interaction between trypsin and pancreatic inhibitor. This is the second interaction beside that of the electrostatic bond between Asp-117 of trypsin and Lys-15 of the inhibitor which we proved earlier.