title: Isolation and activities of the trypsin-modified Vicia angustifolia proteinase inhibitor lacking carboxyl-terminal hexapeptide.
abstract: The Vicia angustifolia proteinase inhibitor was incubated with p-toluenesulfonyl-L-phenylalanine chloromethyl ketone-trypsin (EC 3.4.21.4) and a main product was isolated. The purified product was different to the first trypsin-modified V. angustifolia inhibitor. The C-terminal residues of the new derivative were arginine, which was also the C-terminal of the cleaved antitryptic site; lysine was a newly exposed C-terminal. These results suggest that the new derivative lacks the C-terminal portion of the native inhibitor, which has asparagine at its C-terminus. The liberated C-terminal peptide had the following amino acid sequence: H-Glu-Glu-Val-Ile-Lys-Asn-OH. The derivative lacking the C-terminal hexapeptide still possesses inhibitory activities against trypsin and alpha-chymotrypsin (EC 3.4.21.1), however, its antichymotryptic activity was inactivated by incubation with chymotrypsin at pH 8.0.
mesh_terms: D002918:Chymotrypsin / Q000037:antagonists & inhibitors; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010446:Peptide Fragments / Q000032:analysis; D010944:Plants / Q000032:analysis*; D011480:Protease Inhibitors / Q000302:isolation & purification / Q000494:pharmacology*; D014357:Trypsin; D014361:Trypsin Inhibitors
chemical_list: D010446:Peptide Fragments; D011480:Protease Inhibitors; D014361:Trypsin Inhibitors; D002918:Chymotrypsin; D014357:Trypsin