Comparison of an angiotensin-I-converting enzyme inhibitory peptide from tilapia (Oreochromis niloticus) with captopril: Inhibition kinetics, in vivo effect, simulated gastrointestinal digestion and a molecular docking study.

BACKGROUND In order to utilize tilapia skin gelatin hydrolysates protein, which is normally discarded as industrial waste in the process of fish manufactures, we study the in vivo and in vitro ACE inhibitory activity of peptide, Leu-Ser-Gly-Tyr-Gly-Pro (LSGYGP). Aim to provide a pharmacological basis of the development of minimal side-effects ACE inhibitors by comparative analysis with captopril in molecular docking. RESULTS: This peptide from protein-rich wastes showed excellent ACE-inhibitory activity (IC50 = 2.577 μM) and exhibited a mixed noncompetitive inhibitory pattern with Lineweaver-Burk plots. Furthermore, LSGYGP and captopril groups both showed significant decreases in blood pressure after 6 h and maintained good digestive stability over 4 h. Molecular bond interactions differentiate competitive captopril upon hydrogen bond interactions and Zn(II) interaction. The C-terminal Pro generates three interactions (hydrogen bonds, hydrophilic interactions and Van der Waals interactions) in the peptide and effectively interacts with the S1 and S2 pockets of ACE. CONCLUSION: LSGYGP, with IC50 value of 2.577 μM, has an antihypertensive effect in SHRs. Through comparison with captopril, this study revealed that LSGYGP may be a potential food-derived ACE inhibitory peptide and could act as a functional food ingredient to prevent hypertension. This article is protected by copyright. All rights reserved.