title: Novel angiotensin-I-converting enzyme inhibitory peptides derived from recombinant human alpha s1-casein expressed in Escherichia coli.
abstract: Recombinant human alpha s1-casein expressed in Escherichia coli was purified and digested with trypsin in an attempt to find peptides with angiotensin-I-converting enzyme (ACE) inhibitory activity. Three novel ACE inhibitory peptides, A-II, B-II and C, were isolated and their amino acid sequences identified as Tyr-Pro-Glu-Arg (residues 8-11), Tyr-Tyr-Pro-Gln-Ile-Met-Gln-Tyr (residues 136-143) and Asn-Asn-Val-Met-Leu-Gln-Trp (residues 164-170) respectively. ACE inhibitory activities were measured for the corresponding synthetic peptides, and the ACE IC50 (the amount of peptide causing 50% inhibition of ACE activity) values of A-II, B-II and C estimated to be 132.5, 24.8 and 41.0 mumol/l respectively. Peptides A-II and C were resistant to further digestion by pepsin, whereas peptide B-II was hydrolysed. All three peptides were resistant to digestion by chymotrypsin. These ACE inhibitory peptides may prove useful for oral administration in the treatment of hypertension.
authors.affiliation: Korea Research Institute of Bioscience and Biotechnology, Yusong, Taejon, Korea.
authors.forename: Y K
authors.initials: YK
authors.lastname: Kim
authors.forename: S
authors.initials: S
authors.lastname: Yoon
authors.forename: D Y
authors.initials: DY
authors.lastname: Yu
authors.forename: B
authors.initials: B
authors.lastname: Lönnerdal
authors.forename: B H
authors.initials: BH
authors.lastname: Chung
mesh_terms: D000595:Amino Acid Sequence; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D002364:Caseins / Q000737:chemistry* / Q000235:genetics*; D002851:Chromatography, High Pressure Liquid; D002918:Chymotrypsin / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics*; D015870:Gene Expression; D006801:Humans; D010434:Pepsin A / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D011994:Recombinant Proteins; D014357:Trypsin / Q000378:metabolism
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D002364:Caseins; D010446:Peptide Fragments; D011994:Recombinant Proteins; D002918:Chymotrypsin; D014357:Trypsin; D010434:Pepsin A