title: Angiotensin converting enzyme inhibitory activity of soy protein subjected to selective hydrolysis and thermal processing.
abstract: Soy protein isolate (SPI) and β-conglycinin- and glycinin-rich fractions were hydrolyzed using papain and pepsin. Protein denaturation, profiling, and peptide identification were carried out following DSC, SDS-PAGE, and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The in vitro antihypertensive activity of the hydrolysates was compared by determining the angiotensin converting enzyme (ACE) inhibitory activity. SDS-PAGE and LC-MS/MS analysis confirmed pepsin selectivity to glycinin and papain partial selectivity to β-conglycinin when the protein is least denatured. Both the papain-hydrolyzed SPI and the papain-hydrolyzed β-conglycinin-rich fraction had more than double the ACE inhibitory activity of that of pepsin-hydrolyzed SPI and pepsin-hydrolyzed glycinin-rich fraction. This observation indicated that β-conglycinin is a better precursor for antihypertensive peptides than glycinin. Additionally, the inhibitory activity of the papain-hydrolyzed SPI was thermally stable. This work demonstrated, for the first time, that selective hydrolysis to release peptides with ACE inhibitory activity can be accomplished without inducing extensive hydrolysis and performing unnecessary fractionation.
authors.affiliation: Food Science and Nutrition, University of Minnesota, St. Paul, Minnesota 55108-1038, United States.
authors.forename: Wynnie
authors.initials: W
authors.lastname: Margatan
authors.forename: Kirsten
authors.initials: K
authors.lastname: Ruud
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
authors.forename: Todd
authors.initials: T
authors.lastname: Markowski
authors.forename: Baraem
authors.initials: B
authors.lastname: Ismail
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D052179:Antigens, Plant / Q000378:metabolism; D000959:Antihypertensive Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D055808:Drug Discovery; D005511:Food Handling; D005916:Globulins / Q000378:metabolism; D006358:Hot Temperature; D007700:Kinetics; D010206:Papain / Q000378:metabolism; D010434:Pepsin A / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D007703:Peptidyl-Dipeptidase A / Q000737:chemistry / Q000378:metabolism; D059748:Proteolysis; D011817:Rabbits; D055314:Seed Storage Proteins / Q000378:metabolism; D030262:Soybean Proteins / Q000378:metabolism*
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D052179:Antigens, Plant; D000959:Antihypertensive Agents; D005916:Globulins; D010446:Peptide Fragments; D055314:Seed Storage Proteins; D030262:Soybean Proteins; C013894:beta-conglycinin protein, Glycine max; C011474:glycinin; D007703:Peptidyl-Dipeptidase A; D010206:Papain; D010434:Pepsin A