Three Novel ACE Inhibitory Peptides Isolated From Ginkgo biloba Seeds: Purification, Inhibitory Kinetic and Mechanism

Abstract

Alcalase, dispase, trypsin, and flavourzyme were used to hydrolyze the extracted <i>Ginkgo biloba</i> seeds protein isolate (GPI). The <i>Ginkgo</i> protein hydrolyzates (GPHs) with the maximum degree of hydrolysis (DH) and ACE inhibitory activity were selected, and ultra-filtered to obtain components with different molecular weights (MW) (<1 kDa, 1-3, 3-5, and 5-10 kDa). The components with MW of <1 kDa showed better ACE inhibition (IC₅₀:0.2227 mg/mL). Purification and identification by Sephadex G-15 gel chromatography and LC-MS/MS conferred three new potential ACE inhibitory peptides [TNLDWY (non-competitive suppression mode), IC₅₀: 1.932 mM; RADFY (competitive inhibition modes), IC₅₀:1.35 mM; RVFDGAV (competitive inhibition modes), IC₅₀:1.006 mM]. Molecular docking depicting the inhibitory mechanism for ACE inhibitory peptides indicated that the peptides bound well to ACE and interacted with amino acid residues at the ACE active site.