Table 3.
Summary of Dipeptidyl peptidase (DPP)-IV inhibitory peptides derived from SSTY GI protein.
| Peptide Sequence | Molecular Mass (Da) | Peptide Size | DPP-IV IC50 (µM) | Mode of Inhibition | Peptide Type |
|---|---|---|---|---|---|
| VPGLAL | 569 | 6 | 289.2 ± 11.85 | Competitive | Substrate |
| LPSW | 502 | 4 | 269.7 ± 15.91 | Competitive | Substrate |
| LPLF | 489 | 4 | 463.6 ± 5.52 | Competitive | Substrate |
| LVGLPL | 611 | 6 | >2000 | nd | nd |
| WLQL | 559 | 4 | 432.5 ± 40.31 | Uncompetitive | True inhibitor |
The mode of DPP-IV inhibition was determined using the Lineweaver and Burk double reciprocal representation. nd: not determined, Peptide type was determined using pre-incubation with DPP-IV 3 h at 37 °C, and then injected into LC-MS and also compared inhibition at 500 µM of peptides with absent or present of pre-incubation with DPP-IV. nd: not determined.