On the complex formation between basic pancreatic trypsin inhibitor and TLCK‐, TPCK‐derivatives of β‐trypsin

Abstract

The study of the interaction of the pancreatic inhibitor with different alkylated derivatives of a-and E-trypsin shows that: 1) TLCK~-trypsin forms a complex with pancreatic inhibitor in tris buffer and tris-ethano140% system. 2) TLCK-a-trypsin and TLCK-TPCK-fl-trypsin have lost their ability to complex formation with pancreatic inhibitor. TLCK-ot-trypsin and TLCK-TPCK-#-trypsin are 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.

Proteolytic activity of pseudotrypsin

“…Esterase activity assays were carried out in the same manner as described previously [6] with substrate concentration 0.1 M using a Metrohm Herisau type titrator.…”

Biochemical Aspects of a Serine Protease fromCaesalpinia echinataLam. (Brazilwood) Seeds: A Potential Tool to Access the Mobilization of Seed Storage Proteins

“…As shown in Table 3, the strongest inhibition (about 96%) was observed with TLCK, an irreversible inhibitor of serine proteases. It is possible that alkylation of His residue in CeSP by TLCK leads to chemical modification resulting in the inactivation of the specific active site, which is responsible for the cleavage at positively charged residues at P 1 positions of substrates, as reported by Imhoff and Keil-Dlouha [36]. CeSP was also inhibited by benzamidine (about 50%), an inhibitor of serine proteases, showing the CeSP affinity for Arg residues.…”