Deactivation of soybean agglutinin by enzyme hydrolysis and identification of active peptides from soy proteins

Abstract

A series of experiments was conducted to eliminate the hemagglutination activity of the anti-nutritional factor, soybean agglutinin (SBA). Deglycosylation decreased activity of SBA by 21%, but not as much as denaturation by heat or denaturing reagents (47-77% residual activity). Single enzymes, such as trypsin, chymotrypsin, thermolysin and Endoproteinase Glu-C, did not hydrolyze native SBA, but hydrolyzed heator organic solute-denatured SBA. Even after hydrolysis, activity of SBA still was not fully eliminated (44-62% residual activity). Combinations of enzymes with thermolysin fully deactivated heator organic solute-, such as guanidine hydrochloride and urea, treated SBA. Pepsin and pancreatin hydrolysis fully deactivated native SBA. Tea polyphenols, metal ions, and chelating agents were also tested, and they showed no significant effect in SBA activity. N-acetyl-galactosamine-agrose beads specifically removed SBA from protein mixture, but not fully and the activity was not fully eliminated. In conclusion, SBA needs to be denatured first for enzyme hydrolysis and multiple enzymes are needed to fully deactivate SBA. 1 Department of Food Science and Human Nutrition, Iowa State University, IA 2 Corresponding author, 2312 Food Science Building, Ames, Iowa, 50011, tongwang@iastate.edu, 515-294-5448