Enzyme kinetics, molecular docking, and in silico characterization of canary seed (Phalaris canariensis L.) peptides with ACE and pancreatic lipase inhibitory activity

Abstract

The bioactivity of canary seed peptides (CSP) towards metabolism-regulating enzymes was evaluated. Peptides with angiotensin-converting enzyme (ACE), dipeptidyl peptidase IV (DPP-IV), and pancreatic lipase activity remained stable (p < 0.05) to simulated gastrointestinal digestion (SGD). CSP-SGD were transported efficiently (>10%) through the Caco-2 monolayer, indicating absorption through the intestinal epithelium. Lineweaver-Burk plots demonstrated that CSP-SGD act as mixed-type inhibitors for DPP-IV and α-glucosidase. Furthermore, CSP-SGD were potent as antihypertensive and antiobesity agents. Molecular docking and in silico analyses were targeted to understand CSP-SGD interactions with ACE and pancreatic lipase. ACE-inhibitory peptides (LHPQ, QTPHQ, KPVPR, and ELHPQ) acted as non-competitive inhibitors by destabilization of the transition state and Zn(II) coordination in ACE. The uncompetitive inhibition of pancreatic lipase by peptides (VPPR, LADR, LSPR, and TVGPR) destabilized the open-lid conformation of pancreatic lipase. The results of this study showed that canary seed proteins could serve as a source of biologically active peptides.