Separation, Purification, Structure-Activity Relationship and Molecular Docking of Sesame Angiotension Converting Enzyme Inhibitory Peptides Prepared by Subcritical Water Hydrolysis

Abstract

Angiotension converting enzyme (ACE) inhibitory peptides from high-temperature sesame meal protein hydrolyzed by subcritical water were separated and purified by sequential nanofiltration, ultrafiltration and liquid chromatography, and their structures were identified by liquid chromatography-mass spectrometry (LC-MS). The ACE inhibitory activity was verified using the synthetic oligopeptides. The absorption and metabolism characteristics of the oligopeptides were predicted, a three-dimensional quantitative structure-activity relationship (3D-QSAR) model was established, and molecular docking analysis was carried out. The peptide fraction with molecular mass less than 3 kDa had the strongest ACE inhibitory effect. After further purification, nine ACE inhibitory peptides were identified from peak 1. These peptides could not interfere with the normal physiological activities of the human body. The 3D-QSAR model for LFRAF was successfully established using the comparative molecular force field analysis (CoMFA) method. The positively charged amino acid residues and the introduced large groups on the side chain at the C-terminus of the ACE inhibitory peptides could improve their activity. LFRAF occupied the S2 and S1’ active pockets of the ACE peptides and bund to Zn2+ to inhibit ACE activity. These results indicate that it is feasible to use subcritical water technology to degrade high-temperature sesame meal proteins to prepare ACE inhibitory peptides.

Keywords

• sesame protein; angiotension converting enzyme inhibitory peptide; isolation and purification; structure-activity relationship; safety evaluation