title: Angiotensin I-converting enzyme inhibitory peptides isolated from tofuyo fermented soybean food.
abstract: Angiotensin I-converting enzyme (ACE) inhibitory activity was observed in a tofuyo (fermented soybean food) extract with an IC(50) value of 1.77 mg/ml. Two ACE inhibitors were isolated to homogeneity from the extract by adsorption and gel filtration column chromatography, and by reverse-phase high-performance liquid chromatography (HPLC). The purified substances reacted with 2,4,6-trinitrobenzensulfonic acid sodium salt. The amino acid sequences of these inhibitors determined by Edman degradation were Ile-Phe-Leu (IC(50), 44.8 microM) and Trp-Leu (IC(50), 29.9 microM). The Ile-Phe-Leu sequence is found in the alpha- and beta-subunits of beta-conglycinin, while the Trp-Leu sequence is in the B-, B1A- and BX-subunits of glycinin from soybean. Both of the peptides are non-competitive inhibitors. The inhibitory activity of Trp-Leu was completely preserved after a treatment with pepsin, chymotrypsin or trypsin. Even after successive digestion by these gastrointestinal proteases, the activity remained at 29% of the original value.
authors.affiliation: Department of Bioscience and Biotechnology, Faculty of Agriculture, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa 902-0213.
authors.forename: Megumi
authors.initials: M
authors.lastname: Kuba
authors.forename: Kumi
authors.initials: K
authors.lastname: Tanaka
authors.forename: Shinkichi
authors.initials: S
authors.lastname: Tawata
authors.forename: Yasuhito
authors.initials: Y
authors.lastname: Takeda
authors.forename: Masaaki
authors.initials: M
authors.lastname: Yasuda
mesh_terms: D000595:Amino Acid Sequence; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000302:isolation & purification* / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D010450:Endopeptidases / Q000494:pharmacology; D005285:Fermentation; D006801:Humans; D020128:Inhibitory Concentration 50; D007700:Kinetics; D009842:Oligopeptides / Q000302:isolation & purification* / Q000494:pharmacology; D007703:Peptidyl-Dipeptidase A / Q000187:drug effects; D020539:Sequence Analysis, Protein; D045730:Soy Foods; D013025:Glycine max
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D009842:Oligopeptides; D010450:Endopeptidases; D007703:Peptidyl-Dipeptidase A