Porcine skeletal muscle troponin is a good source of peptides with Angiotensin-I converting enzyme inhibitory activity and antihypertensive effects in spontaneously hypertensive rats.
In the search for novel peptides that inhibit the angiotensin I-converting enzyme (ACE), porcine skeletal troponin was hydrolyzed with pepsin, and the products were subjected to various types of chromatography to isolate active peptides. Glu-Lys-Glu-Arg-Glu-Arg-Gln (EKERERQ) and Lys-Arg-Gln-Lys-Tyr-Asp-Ile (KRQKYDI) were identified as active peptides, and their 50% inhibitory concentrations were found to be 552.5 and 26.2 microM, respectively. These are novel ACE inhibitory peptides, and the activity of KRQKYDI was the strongest among previously reported troponin-originated peptides. KRQKYDI was slowly hydrolyzed by treatment with ACE, and kinetic studies indicated that this peptide was a competitive inhibitor of the enzyme. When KRQKYDI was administered orally to spontaneously hypertensive rats (SHR) at a dose of 10 mg/kg, a temporary antihypertensive activity was observed at 3 and 6 h after administration.
Katayama
Kazunori
K
Department of Biochemistry and Applied Biosciences, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuen Kibanadai Nishi, Miyazaki 889-2192, Japan.
Anggraeni
Henny Endah
HE
Mori
Takahiro
T
Ahhmed
Abdulatef M
AM
Kawahara
Satoshi
S
Sugiyama
Masaaki
M
Nakayama
Tatsuo
T
Maruyama
Masugi
M
Muguruma
Michio
M
D000595:Amino Acid Sequence; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology; D000818:Animals; D006973:Hypertension / Q000188:drug therapy; D018482:Muscle, Skeletal / Q000737:chemistry*; D010434:Pepsin A / Q000378:metabolism; D010446:Peptide Fragments / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D011918:Rats, Inbred SHR; D013552:Swine; D014336:Troponin / Q000737:chemistry* / Q000378:metabolism
D000806:Angiotensin-Converting Enzyme Inhibitors; D010446:Peptide Fragments; D014336:Troponin; D010434:Pepsin A