Preparation and Characterization of Dipeptidyl Peptidase-IV Inhibitory Peptides from Yeast Hydrolysates

Dipeptidyl peptidase-IV (DPP-IV) inhibitors have been found in protease hydrolysates of many animal and plant proteins; however, there is little information about DPP-IV inhibitors from microorganisms. The aim of this study was to explore and elucidate the mechanisms of DPP-IV inhibitory peptides isolated from yeast hydrolysates. Results revealed that yeast hydrolysates could inhibit 50% DPP-IV activity at 0.84 mg/mL. After ethanol extraction and gel filtration, the active components in yeast hydrolysates were significantly enriched, and five novel DPP-IV inhibitory peptides were found by in silico and in vitro methods. Peptide WPLP, with the lowest IC50 of 178 μM, was demonstrated to be stable under heating, pH-shifting treatment, simulated digestion, and DPP-IV incubation. Moreover, the combination of WPLP and sitagliptin at low concentration showed a moderate synergistic effect on DPP-IV inhibition. These findings suggest that yeast-derived DPP-IV inhibitory peptides could serve as a functional food ingredient for diabetes management.