Release of dipeptidyl peptidase IV inhibitory peptides from salmon ( Salmo salar ) skin collagen based on digestion–intestinal absorption in vitro

Summary Inhibition of dipeptidyl peptidase IV (DPP‐IV) was considered to be a crucial target for type 2 diabetes, and food‐derived peptides were superior source of DPP‐IV inhibitory peptides. The purpose of this investigation was to identify inhibitory peptides from salmon skin collagen using simulated digestion combined with Caco‐2 cell monolayer membrane model. The analysis in silico showed that TKLPAVF and YLNF were potential inhibitory peptides. Determination of the inhibition activity showed that the IC 50 values of TKLPVAF and YLNF were 242.10 ± 3.40 and 146.90 ± 4.40 µ m , respectively. Molecular docking results showed that seven hydrogen bonds were formed between YLNF and key residues of DPP‐IV. YLNF may be considered a novel DPP‐IV inhibitory peptide. In addition, YLNF could be transported by Caco‐2 cell monolayer membrane in intact, and the apparent permeability coefficient value was (3.54 ± 0.34) × 10 ‐6 cm s −1 at 5 m m .