Kinetic and thermodynamic-based studies on the interaction mechanism of novel R. roxburghii seed peptides against pancreatic lipase and cholesterol esterase

Pancreatic lipase (PL) and cholesterol esterase (CE) are vital digestive enzymes that regulate lipid digestion. Three bioactive peptides (LFCMH, RIPAGSPF, YFRPR), possessing enzyme inhibitory activities, were identified in the seed proteins of R. roxburghii. It is hypothesized that these peptides could inhibit the activities of these enzymes by binding to their active sites or altering their conformation. The results showed that LFCMH exhibited superior inhibitory activity against these enzymes compared to the other peptides. The inhibition mechanisms of the three peptides were identified as either competitive or mixed, according to inhibition models. Further studies have shown that peptides could bind to the active sites of enzymes, thus affecting their spatial conformation and restricting substrate entry into the active site. Molecular simulation further proved that hydrogen bonds and hydrophobic interactions played a vital role in the binding of peptides to enzymes. This study enriches our understanding of interaction mechanisms of peptides on PL and CE.