Properties and human origin of two angiotensin-I-converting enzyme inhibitory peptides isolated from a tryptic hydrolysate of human serum albumin.
Two angiotensin-I-converting enzyme (ACE) inhibitory peptides were isolated from a tryptic hydrolysate of human serum albumin (HSA). The peptides were identified by sequencing and other analyses as Ala-Trp and the nonapeptide Ala-Phe-Lys-Ala-Trp-Ala-Val-Ala-Arg (human albutensin A), corresponding to f(213-214) and f(210--218) of HSA, respectively. Synthetic versions of both peptides had previously been shown to have ACE inhibitory activity. The present results are the first to show that these peptides have a potential natural origin in humans. Additional studies were done to define the inhibitory properties of these peptides, as they had not been previously reported. The dipeptide and nonapeptide showed dose-dependent inhibition of ACE, with IC50 values of 12 and 1.7 micromol/l, respectively. Lineweaver-Burk plots suggested that Ala-Trp is a competitive inhibitor, and that human albutensin A is a noncompetitive inhibitor.
Nakagomi
K
K
Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Japan,. nakagomi@ms.toyama-mpu.ac.jp
Ebisu
H
H
Sadakane
Y
Y
Fujii
N
N
Akizawa
T
T
Tanimura
T
T
D000302:Adrenal Cortex / Q000378:metabolism; D000450:Aldosterone / Q000378:metabolism; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000302:isolation & purification / Q000494:pharmacology*; D001920:Bradykinin / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D004151:Dipeptides / Q000302:isolation & purification / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006801:Humans; D006868:Hydrolysis; D009842:Oligopeptides / Q000302:isolation & purification / Q000494:pharmacology*; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism / Q000502:physiology; D012709:Serum Albumin / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology*; D014357:Trypsin / Q000378:metabolism*
D000806:Angiotensin-Converting Enzyme Inhibitors; D004151:Dipeptides; D009842:Oligopeptides; D012709:Serum Albumin; C418002:albutensin A; D000450:Aldosterone; D007703:Peptidyl-Dipeptidase A; D014357:Trypsin; D001920:Bradykinin