Effects of high hydrostatic pressure treatment: Identification and characterization of snakehead-muscle-protein-based angiotensin-converting-enzyme-inhibitory peptides

The main targets for antihypertensive peptides are renin and angiotensin-converting enzyme (ACE). Snakehead muscle protein (SMP)-based peptides generated as enzymatic protein hydrolysates under high hydrostatic pressure (HHP) contain a pool of peptides with potential natural ACE-inhibitory activity. The 12 peptides identified possess unique properties, including net charge (Glu and Lys) and hydrophobicity (Val and Pro). These peptides were docked into the ACE catalytic site, resembling the mode of inhibition exerted by lisinopril, an effective synthetic antihypertensive drug. In particular, the long-chain peptide identified (AIGTGKTASPQQAQE) exhibited potent ACE-inhibitory activity with an IC50 value of 0.076 mu mol/L. The degree of inhibition of this peptide correlated with hydrogen bond interactions involving ACE residues Glu162, Gln281 and Lys511. These findings indicated that SMP-based peptides can be a potential natural ACE-inhibitory ingredient for the formulation of functional foods and nutraceuticals.