Isolation and Characterization of Four Isoinhibitors from Cowpea (Vigna unguiculata (L.) Walp.) Seeds

Authors : Reda Helmy Ahmed SAMMOUR

Pages : 207-215

View : 15 | Download : 14

Publication Date : 2006-12-01

Article Type : Research Paper

Abstract :Four isoinhibitors of trypsin have been isolated from the cowpea, Vigna unguiculata insert ignore into journalissuearticles values(L.); Walp., in a highly purified state, as indicated by Urea-SDS-polyacrylamide gel electrophoresis, equilibrium chromatography, and amino acid analysis. The amino acid composition was characterized by the absence of free -SH groups, high half-cysteine, and the absence of tryptophan and methionine in isoinhibitors II and III. Isoinhibitor II contained 96 amino acid residues, whereas isoinhibitor III contained 80. Isoinhibitor II had lysine in the reactive site, while isoinhibitor III had arginine. Isoinhibitor IA inhibited trypsin only, while isoinhibitors IB, II, and III inhibited both trypsin and a-chymotrypsin, indicating that each one had an independent site for each enzyme insert ignore into journalissuearticles values(trypsin and chymotrypsin);. The amino acid sequence of isoinhibitor III exhibited a close homology with Macrotyloma axillare DE3 insert ignore into journalissuearticles values(81%);, lima bean IV insert ignore into journalissuearticles values(78%);, Macrotyloma axillare DE4 insert ignore into journalissuearticles values(72%);, and mung bean insert ignore into journalissuearticles values(65%); isoinhibitors.
Keywords : CPTI, cowpea trypsin inhibitor, N a benzoyl L arginine p nitroanilide BAPNA, P nitrophenyl P guanidinobenzoate HCl NPGB, N benzoyl L tyrosine ethyl ester ins