title: Acein-1, a novel angiotensin-I-converting enzyme inhibitory peptide isolated from tryptic hydrolysate of human plasma.
abstract: A novel angiotensin-I-converting enzyme (ACE) inhibitory peptide, designated acein-1, was isolated from the tryptic hydrolysate of human plasma. Gel filtration and cation exchange chromatography were performed to purify this peptide, followed by reversed-phase gradient and isocratic high-performance liquid chromatography. Acein-1 was found to be a heptapeptide, Tyr-Leu-Tyr-Glu-Ile-Ala-Arg, corresponding to f(138-144) of human serum albumin. The synthetic heptapeptide, hexapeptide (Tyr-Leu-Tyr-Glu-Ile-Ala, des-7R acein-1) and octapeptide (Tyr-Leu-Tyr-Glu-Ile-Ala-Arg-Arg, acein-1R) showed dose-dependent inhibitions of ACE, and their IC50 values were 16 micromol/l, 500 micromol/l and 86 micromol/l, respectively. Acein-1 might be a non-competitive inhibitor, while acein-1R may be an uncompetitive inhibitor, as shown by Lineweaver-Burk plots.
authors.affiliation: Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Sugitani, Japan. nakagomi@ms.toyama-mpu.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Nakagomi
authors.forename: A
authors.initials: A
authors.lastname: Fujimura
authors.forename: H
authors.initials: H
authors.lastname: Ebisu
authors.forename: T
authors.initials: T
authors.lastname: Sakai
authors.forename: Y
authors.initials: Y
authors.lastname: Sadakane
authors.forename: N
authors.initials: N
authors.lastname: Fujii
authors.forename: T
authors.initials: T
authors.lastname: Tanimura
mesh_terms: D000595:Amino Acid Sequence; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000097:blood / Q000737:chemistry* / Q000302:isolation & purification; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D006801:Humans; D006868:Hydrolysis; D007700:Kinetics; D013058:Mass Spectrometry; D010446:Peptide Fragments / Q000737:chemistry* / Q000302:isolation & purification; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism; D012709:Serum Albumin / Q000737:chemistry* / Q000302:isolation & purification / Q000502:physiology; D000075462:Serum Albumin, Human; D014357:Trypsin
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D010446:Peptide Fragments; D012709:Serum Albumin; C115924:acein 1; D007703:Peptidyl-Dipeptidase A; D014357:Trypsin; D000075462:Serum Albumin, Human