Screening and mechanism of six angiotensin I-converting eneyme inhibitory peptides from protein hydrolysate of Coregonus peled visceral: A combined in computer and in vitro study

Abstract

Coregonus peled visceral can be regarded as a rich source of bioactive peptides. The purpose of this study is to screen peptides with high angiotensin I-converting eneyme (ACE) inhibitory activity from protein hydrolysate of Coregonus peled visceral prepared by trypsin, and analyze the inhibitory mechanisms of prepared peptides. The results showed that the UF-4 (MW < 3 kDa) had the highest ACE inhibitory activity of 73.55% (2 mg/ml). UF-4 was separated by Sephadex G-25 column and collected three fractions (F1, F2 and F3), and 397 peptides were detected from F1 fraction, and 6 peptides were screened by silico methods as potential antihypertensive peptides. FPGAKP formed 9 hydrogen bond interactions with Ala354, Tyr523, Glu384 in S1 pocket; His353 in S2 pocket; 5 hydrogen bond interactions with Thr282, Ala356, Arg522, Arg522, and His387 near the active sites. FPGAKP has the highest ACE inhibitory activity (IC50 = 0.039 mg/ml) and exhibits competitive inhibition. The total content of β-sheet and α-helix in the secondary structure of FPGAKP was the highest (80.22%). Studies have shown that the ACE inhibitory activity of the peptide mainly depends on the number of hydrogen bonds formed with the key active site of ACE and the content of β-sheet and α-helix. The results indicated that FPGAKP has the value of further research as a substitute for antihypertensive drugs.