ACE inhibitory activity and gastrointestinal digestion stability of umami peptides IIVFGRQLL from yeast extract

Hypertension has emerged as a major factor detrimental to human health. Umami peptide IIVFGRQLL from yeast has a certain ACE inhibitory activity (IC₅₀: 59.35 μM) at 0.14 mg/mL. Moreover, IIVFGRQLL could regulate the systolic blood pressure of spontaneously hypertensive rats model indicating its potential antihypertensive effect. The changes in ACE inhibitory activity and peptide sequence during the digestion were investigated based on the ACE inhibition assays, simulated gastrointestinal digestion, and LC-MS/MS. The ACE inhibitory activity of IIVFGRQLL decreased by 39.0% after digestion. It was hydrolyzed into 5 peptide fragments, among which IVF took the biggest share followed by IVFG, VF, FGR, and RQL. The inhibitory rate of IVF (78.70%), FGR (86.30%), and VF (83.50%) was higher than that of IIVFGRQLL (60.11%). The molecular docking results revealed all the peptides interacted with active residues related to Zn²⁺ and S1 pocket in ACE. Besides, IVF, FGR and RQL showed increased electrostatic interaction with Zn²⁺. These results provide theoretical support for the future exploration of umami peptide as a food additive or seasoning to alleviate hypertension.