Preparation of Angiotensin Ⅰ-Converting Enzyme Inhibitory Peptides from Haliotis discus hannai Mantle Collagen

In order to improve the utilization of Haliotis discus hannai mantle, collagen purified from it was hydrolyzed by trypsin and pepsin to prepare angiotensin Ⅰ-converting enzyme (ACE) inhibitory peptides. The hydrolysate was purified by sequential ultrafiltration, Superdex^TM peptide 10/300 GL gel filtration chromatography and high performance liquid chromatography (HPLC). Three ACE inhibitory peptides, SGEVGQ, QRGPAGAQGPQ and GPPGPAGAR, were obtained . Among them, GPPGPAGAR had the highest ACE inhibitory activity with a half maximal inhibitory concentration (IC₅₀) of 177.1 μmol/L. Molecular docking results showed that GPPGPAGAR mainly acted on the S₁ active pocket of ACE and the inhibitory mode was similar to that of lisinopril. GPPGPAGAR still showed high ACE inhibitory activity after simulated gastrointestinal digestion. This study will provide a reference for deep processing of abalone mantle and the development of ACE inhibitory peptides.