Separation and identification of ACE inhibitory peptides from lizard fish proteins hydrolysates by metal affinity-immobilized magnetic liposome

Abstract

Purification of peptides responsible for angiotensin I-converting enzyme (ACE) inhibitory activity from highly complex protein hydrolysates is difficult. Affinity chromatography is a powerful method for purification of peptides. In this study, a metal affinity-immobilized magnetic liposome (MA-IML) was prepared using lipid, N-hexadecyl iminodiacetic acid (HIDA) and magnetic nanoparticles made of FeCl₃·6H₂O and FeCl₂·4H₂O as main materials. MA-IML was used to adsorb ACE inhibitory peptides from lizard fish proteins hydrolysates. The optimal pH of adsorption solution was 8.5. The peptide sample adsorbed by MA-IML was separated by reverse phase-high performance liquid chromatography (RP-HPLC). Upon amino acid sequence analysis and verification, an ACE inhibitory peptide with IC₅₀ value of 108 μM was identified to be VYP. Molecular docking results indicated that VYP bound to ACE via multiple binding sites. The present study demonstrated that MA-IML might be a useful tool for separating ACE inhibitory peptides from proteins hydrolysates.