Identification of a Novel Post-digestion Angiotensin I-Converting Enzyme Inhibitory Peptide from Silver Prussian Carp (Carassius auratus gibelio) Roe

Proteins of aquatic products are potential sources of bioactive peptides. This study attempted to screen 29 kinds of aquatic products with the highest angiotensin I-converting enzyme (ACE) inhibitory activity and to identify the active peptide. Results showed that the enzyme hydrolysate of silver Prussian carp roe exhibited the highest ACE inhibitory rate before (64.71%) and after (53.82%) digestion. LAKVAP identified from the enzymatic extract of silver Prussian carp roe was a competitive inhibitor, with an ACE inhibitory rate of 95.33%. The molecular docking study suggested that LAKVAP formed hydrogen bonds with S2 active sites (Gln281, His 353, and His513) and made coordinate bonds with Zn2+ (His383) of ACE, which contributed to the interaction between ACE and peptide. The results suggested that silver Prussian carp roe proteins could be suitable materials for ACE inhibitory peptide preparation, and LP-6 might be potentially beneficial as an antihypertensive agent.