Isolation of Acidic and Basic Polypeptides in Soybean Glycinin and Their Characteristics in Enzymatic Cross-linking
XIA Jia-heng
GONG Yu-qing
WU Lei-lei
WANG Yan
YANG An-shu
CHEN Hong-bing
Abstract：Using soybean as the raw material,the acidic and basic polypeptides of glycinin were isolated,and the differences between their effects in microbial transglutaminase (MTG)-mediated cross-linking were explored.Glycinin was obtained with a purity of more than 94％ from soybean protein by isoelectric precipitation,gel filtration chromatography,and affinity chromatography.The acidic and basic polypeptides were isolated by isoelectric precipitation after heat denaturation and reduction with β-mercaptoethanol,and then characterized by electrophoresis and amino acid analysis.Furthermore,sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and dissolution experiments were performed to determine the effects of acidic and basic polypeptides on enzymatic cross-linking and the solubility of the cross-linked products.The results suggested that both the acidic and basic potypeptides were effective substrates for MTG and could participate in the cross-linking reaction to form polymers with high molecular weight;however,the reaction rate of basic polypeptides was lower than that of acidic polypeptides.The differences between the acidic and basic polypeptides in the cross-linking reaction were slightly affected by the glutamine and lysine residue content,and were significantly affected by the hydrophobic amino acid content.
Keywords：glycininacidic and basic polypeptidesprotein purificationmicrobial transglutaminaseenzymatic cross-linking
Publication Date：2017-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：6( 55-60 )