Analysis of the Structure and Activity of Dipeptidyl Peptidase IV (DPP-IV) Inhibitory Oligopeptides from Sorghum Kafirin

Potential dipeptidyl peptidase IV (DPP-IV) inhibitory oligopeptides from sorghum kafirin were developed using in silico and in vitro methodologies for the management of diabetes. Twenty-eight peptides with 5-10 residues were identified from the papain hydrolysates of sorghum kafirin. Sixteen nontoxic DPP-IV inhibitory peptides were screened with a computer method based on molecular docking. Molecular docking revealed that LPFYPQ (LP6), GPVTPPILG (GP9), and LPFYPQGV (LP8) effectively inactivated DPP-IV by binding to its active sites with a low interaction energy. An in silico analysis of these three inhibitory oligopeptides indicated that they were all bound to the S1 and S2 active pockets of DPP-IV through hydrogen bonds and hydrophobic interactions. The in vitro inhibitory activity was also verified. The DPP-IV inhibitory activities of LP6 and LP8 decreased after gastric digestion and remained stable after intestinal digestion, and the GP9 inhibitory activity remained stable after gastrointestinal digestion. Experimental results from Caco-2 cells showed further inhibitory effects of oligopeptides on DPP-IV. The results are relevant to the exploration of biofunctional DPP-IV inhibitory peptides from sorghum as a treatment for patients with diabetes or in medical research.

Automated summary

This study developed potential dipeptidyl peptidase IV (DPP-IV) inhibitory oligopeptides from sorghum kafirin using in silico and in vitro methods. The inhibitory activities of these peptides were confirmed through molecular docking and in vitro experiments, and their potential in the treatment of diabetes was highlighted.