Isolation of acein-2, a novel angiotensin-I-converting enzyme inhibitory peptide derived from a tryptic hydrolysate of human plasma.
We previously described a novel angiotensin-I-converting enzyme (ACE) inhibitory peptide, designated Acein-1, that was isolated from a tryptic hydrolysate of human plasma. We now report a second such inhibitory peptide, Acein-2 obtained from the same hydrolysate. The peptide was purified by gel filtration and cation exchange chromatography followed by reversed-phase gradient and isocratic high performance liquid chromatography. Acein-2 was found to be a tripeptide, Leu-Ile-Tyr, which is thought to correspond to f(518-520) of human alpha2-macroglobulin. The synthetic tripeptide showed a potent dose-dependent inhibition of ACE, with an IC(50) value of 0.82 micromol/l. Lineweaver-Burk plots suggested that Acein-2 as well as the previously described Acein-1 are non-competitive inhibitors.
Nakagomi
K
K
Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama, Japan. nakagomi@ms.toyama-mpu.ac.jp
Yamada
R
R
Ebisu
H
H
Sadakane
Y
Y
Akizawa
T
T
Tanimura
T
T
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000302:isolation & purification*; D000959:Antihypertensive Agents / Q000302:isolation & purification; D005591:Chemical Fractionation; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D006801:Humans; D007700:Kinetics; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification*; D010949:Plasma / Q000737:chemistry*; D012709:Serum Albumin / Q000737:chemistry / Q000302:isolation & purification*; D000075462:Serum Albumin, Human; D014357:Trypsin; D000511:alpha-Macroglobulins / Q000737:chemistry
D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D010446:Peptide Fragments; D012709:Serum Albumin; C405645:acein-2; D000511:alpha-Macroglobulins; D014357:Trypsin; D000075462:Serum Albumin, Human