Isolation and characterization of a novel angiotensin-converting enzyme-inhibitory tripeptide from enzymatic hydrolysis of soft-shelled turtle (Pelodiscus sinensis) egg white: in vitro, in vivo, and in silico study.
In this study, a novel angiotensin-converting enzyme (ACE)-inhibitory tripeptide (IVR) was isolated and identified from unfertilized soft-shelled turtle egg white (SSTEW). The IC50 value of IVR was measured in vitro as low as 0.81 ± 0.03 μM, and its inhibition type was suggested as competitive according to the Lineweaver-Burk plot. This peptide can be generated from either thermolysin followed by trypsin digestion (two stages) or only trypsin digestion (one stage). Quantitative LC-MS/MS analysis indicated that two-stage digestion gave 3.14 ± 0.17 mg of IVR from 1 g of SSTEW, better than that from one-stage digestion (1.31 ± 0.12 mg). In vivo antihypertensive activity of the tripeptide IVR after single oral administration (0.1 and 1 mg/kg of body weight) led to a significant reduction in systolic blood pressure 2-4 h after administration in spontaneously hypertensive rats. In addition, the binding mechanism of IVR has been rationalized through docking simulations using the testicular ACE (tACE)-lisinopril complex at 2 Å resolution (PDB 108A ). The best docking pose was located at the tACE catalytic site resembling the mode of inhibition exerted by lisinopril, an effective hypertensive synthetic drug. The degree of inhibition of this peptide correlated with the H-bond interaction between the C-terminal of IVR and Lys511 and Tyr520 residues of tACE, a significant inhibitor registration for lisinopril. This study illustrated that IVR behaves as a transition-state analogue inhibitor and is useful in therapeutic intervention for blood pressure control. To the best of our knowledge, this is the first report of an efficient ACE-inhibitory tripeptide generated from the unfertilized egg of soft-shelled turtle.
Department of Food Science, ‡Department of Biological Science and Technology, §Department of Veterinary Medicine, ∥Research Center for Austronesian Medicine and Agriculture, and ⊥Research Center for Tropic Agriculture, National Pingtung University of Science and Technology , Neipu, Pingtung 91201, Taiwan.
Reynetha D S
RD
Rawendra
Aisha
Sin-Hong
SH
Chen
Chi-I
CI
Chang
Wen-Ling
WL
Shih
Tzou-Chi
TC
Huang
Ming-Huei
MH
Liao
Jue-Liang
JL
Hsu
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000008:administration & dosage / Q000737:chemistry* / Q000302:isolation & purification*; D000818:Animals; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000737:chemistry* / Q000302:isolation & purification*; D055162:Biocatalysis; D001794:Blood Pressure; D004529:Egg White / Q000737:chemistry*; D006801:Humans; D006973:Hypertension / Q000188:drug therapy / Q000503:physiopathology; D007700:Kinetics; D008297:Male; D062105:Molecular Docking Simulation; D010455:Peptides / Q000008:administration & dosage / Q000737:chemistry* / Q000302:isolation & purification*; D007703:Peptidyl-Dipeptidase A / Q000737:chemistry / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR; D014357:Trypsin / Q000737:chemistry; D014426:Turtles
D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D010455:Peptides; D007703:Peptidyl-Dipeptidase A; D014357:Trypsin
ACE inhibitor; LC−MS/MS; lysozyme C; soft-shelled turtle egg; tripeptide