Identification of dipeptidyl peptidase IV inhibitory peptides from rapeseed proteins
Haixi You, Yu Zhang, Tianliang Wu, Juanrui Li, Liying Wang, Zhipeng Yu, Jingbo Liu, Xuebo Liu, Long Ding
Abstract
This paper aims to investigate the dipeptidyl peptidase IV (DPP-IV) inhibitory peptides from rapeseed proteins. Results showed that rapeseed protein hydrolysates by simulated gastrointestinal digestion had DPP-IV inhibitory activities. Twenty rapeseed-derived peptides with potential DPP-IV inhibitory activity were selected by an in silico approach and 12 of them were determined with DPP-IV inhibitory activities. Finally, 4 peptides IPK, LPR, VPHL and IPNQT were successfully identified from the rapeseed protein hydrolysate by LC-MS/MS and IPK showed the highest DPP-IV inhibitory activity with IC50 of 44.40 ± 2.18 μmol/L or 46.28 ± 3.62 μmol/L with Gly-Pro-pNA or Gly-Pro-AMC as substrate, respectively. IPK behaved as a competitive inhibitor and was predicted to form attractive charge, hydrophobic and hydrogen bond interactions with the residues located in the S1 and S2 pocket of DPP-IV. This result indicates that rapeseed proteins are prominent sources for DPP-IV inhibitory peptides and have the potential for the management of type 2 diabetes.