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Dipeptidyl peptidase IV inhibitory peptides from Chlorella vulgaris: in silico gastrointestinal hydrolysis and molecular mechanism

Zhu, Qiaosha, Chen, Xujun, Wu, Junjie, Zhou, Yan, Qian, Yang, Fang, Ming, Xie, Jingli, Wei, Dongzhi
European food research & technology 2017 v.243 no.10 pp. 1739-1748
Chlorella vulgaris, blood serum, dipeptidyl-peptidase IV, food research, gastrointestinal system, hydrogen bonding, hydrolysis, hydrophobic bonding, inhibitory concentration 50, mice, molecular models, peptide libraries, protein content, proteins
Chlorella vulgaris: is a nutritional food with high protein content. Thus, 43 protein sequences from C. vulgaris were in silico gastrointestinal digested with the aid of BIOPEP. A peptide library of 468 di- and tri-peptides was built from the produced peptides. Six peptides, AAR, VPA, VPW, IPL, IPR, and PPL, were selected for DPP-IV inhibitory assay based on their sequence feature with Pro or Ala at the second N-terminal site. VPA, VPW, IPL, and IPR had potency of DPP-IV inhibition. VPW and IPR with the same N-terminal and second N-terminal sites as those of diprotin A (IPI) and diprotin B (VPL) achieved relative inhibitory IC₅₀ value of 6.4 and 6.9 versus IPI. These peptides were further demonstrated gastrointestinal stable in vitro and could also inhibit the DPP-IV in mouse serum. Molecular docking illustrated the inhibitory mechanism of VPW and IPR. Both VPW and IPR binding with DPP-IV through hydrogen bonds, van Edward Mars interactions, and hydrophobic interactions. However, VPW formed more stable interaction with DPP-IV. The results suggested that C. vulgaris proteins would be a good source for DPP-IV inhibitory peptides.