title: Identification of a novel angiotensin-I-converting enzyme inhibitory peptide corresponding to a tryptic fragment of bovine beta-lactoglobulin.
abstract: The angiotensin-I-converting enzyme (ACE) inhibitory activity of a tryptic digest of bovine beta-lactoglobulin (beta-lg) was investigated. Intact beta-lg essentially did not inhibit ACE while the tryptic digest gave an 84.3% inhibition of ACE. Peptide material eluting between 20 and 25% acetonitrile during C18 solid-phase extraction of the beta-lg tryptic digest inhibited ACE by 93.6%. This solid-phase extraction fraction was shown by mass spectroscopy to contain beta-lg f(142-148). This peptide had an ACE IC50 value of 42.6 micromol/l. The peptide was resistant to further digestion with pepsin and was hydrolysed to a very low extent with chymotrypsin. The contribution of specific amino acid residues within the peptide to ACE inhibitory activity and the potential application of this peptide as a nutraceutical is discussed.
authors.affiliation: Teagasc, National Dairy Products Research Centre, Fermoy, Co. Cork, Ireland.
authors.forename: M M
authors.initials: MM
authors.lastname: Mullally
authors.forename: H
authors.initials: H
authors.lastname: Meisel
authors.forename: R J
authors.initials: RJ
authors.lastname: FitzGerald
mesh_terms: D000595:Amino Acid Sequence; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000737:chemistry* / Q000494:pharmacology*; D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D002918:Chymotrypsin; D007700:Kinetics; D007782:Lactoglobulins / Q000737:chemistry* / Q000494:pharmacology*; D010434:Pepsin A; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D010449:Peptide Mapping; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism*; D011817:Rabbits; D014357:Trypsin
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D007782:Lactoglobulins; D010446:Peptide Fragments; D007703:Peptidyl-Dipeptidase A; D002918:Chymotrypsin; D014357:Trypsin; D010434:Pepsin A