Virtual Screening of GLP-1-Secreting Peptides from Pea Protein Hydrolysates via Peptide Transporter 1 (PepT1) Activation-Based Molecular Docking

Dietary proteins regulate glucose homeostasis via intestinal protein sensing-induced glucagon-like peptide 1 (GLP-1) secretion. However, the reported GLP-1-secreting peptides derived from dietary proteins are few, and studies regarding GLP-1-secreting peptide identification by traditional separation and purification methods are laborious. Herein, we have rapidly virtual-screened two GLP-1 secreting peptides from pea protein hydrolysates (PPHs) by peptidomic analysis and molecular docking with peptide transporter 1 (PepT1). PPH-stimulated GLP-1 secretion decreased after adding the PepT1 antagonist 4-aminobenzoic acid (4-AMBA), indicating that PepT1 activation was involved in PPH-induced GLP-1 secretion in NCI-H716 cells. Subsequently, 307 tripeptides in PPHs were obtained through peptidomic analysis. Among them, two GLP-1-secreting peptides, FLR and LRW, were identified via PepT1 activation-based molecular docking. FLR and LRW (1 mg/mL) increased GLP-1 levels to 170.20% ± 27.83% and 272.37% ± 45.96%, respectively (p < 0.05). More importantly, molecular docking implied that the interactions between peptides and the active center of PepT1 (especially Glu595, Asn329, and Asn171 in the N-pocket and Arg27 in the C-pocket) were crucial for peptide activity in stimulating GLP-1 secretion. Our study suggested that the combination of peptidomics and PepT1 activation-based molecular docking is a promising approach for identification of GLP-1-secreting peptides.