Abstract：
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.
摘要：
膳食蛋白通过肠道蛋白感应诱导的胰高血糖素样肽1（GLP-1）分泌调节葡萄糖稳态。然而,报道的来自膳食蛋白质的GLP-1分泌肽很少，用传统的分离和纯化方法鉴定GLP-1分泌肽的研究是费力的。在这里，我们通过肽酶分析和与肽转运蛋白1(PepT1)的分子对接,从豌豆蛋白水解物(PPHs)中快速虚拟筛选了两种GLP-1分泌肽.添加PepT1拮抗剂4-氨基苯甲酸（4-AMBA）后，PPH刺激的GLP-1分泌减少，表明PepT1激活参与PPH诱导的NCI-H716细胞GLP-1分泌。随后，通过肽分析获得PPH中的307种三肽。其中,两种GLP-1分泌肽，FLR和LRW,通过基于PepT1激活的分子对接鉴定。FLR和LRW（1mg/mL）将GLP-1水平提高到170.20%±27.83%和272.37%±45.96%，分别为(p<0.05)。更重要的是,分子对接表明，肽与PepT1活性中心（尤其是N口袋中的Glu595，Asn329和Asn171以及C口袋中的Arg27）之间的相互作用对于刺激GLP-1分泌的肽活性至关重要。我们的研究表明，肽酶和基于PepT1激活的分子对接的组合是鉴定GLP-1分泌肽的有前途的方法。
