Identification of the DPP-IV Inhibitory Peptides from Donkey Blood and Regulatory Effect on the Gut Microbiota of Type 2 Diabetic Mice

After being treated with protease K, peptides extracted from donkey blood were separated, identified, and characterized. The results showed that Sephadex G-25 medium purified with MW < 3 kDa had the highest dipeptidyl peptidase IV (DPP-IV) inhibition capacity. Three-hundred-and-thirty-four peptides were identified with UPLC-MS/MS. Peptide Ranker and molecular docking analysis were used to screen active peptides, and 16 peptides were finalized out of the 334. The results showed that the lowest binding energy between P7(YPWTQ) and DPP-IV was -9.1, and the second-lowest binding energy between P1(VDPENFRLL) and DPP-IV was -8.7. The active peptides(MW < 3 kDa) could cause a reduction in the fasting blood glucose levels of type 2 diabetic mice, improve glucose tolerance, and facilitate healing of the damaged structure of diabetic murine liver and pancreas. Meanwhile, the peptides were found to ameliorate the diabetic murine intestinal micro-ecological environment to a certain extent.

Automated summary

This study identified and characterized peptides extracted from donkey blood. Sephadex G-25 medium with MW < 3 kDa showed the highest inhibition capacity of dipeptidyl peptidase IV (DPP-IV). UPLC-MS/MS identified 334 peptides, out of which 16 active peptides were finalized through screening and molecular docking analysis. These active peptides (MW < 3 kDa) were found to improve blood glucose levels and glucose tolerance in type 2 diabetic mice, facilitate the healing of damaged liver and pancreas structure, and to some extent, enhance the intestinal micro-ecological environment of diabetic mice.