Ngamsuk, Samuchaya, and Jue-Liang Hsu. “Identification of dipeptidyl peptidase IV inhibitory peptides derived from gac seed protein hydrolysate using hydrophilic interaction liquid chromatography and reversed-phase high-performance liquid chromatography.” Agriculture and Natural Resources 56.4 (2022): 847-856. https://doi.org/10.34044/j.anres.2022.56.4.19
Importance of the work: Dipeptidyl peptidase IV (DPPIV) plays a critical role in Type 2 diabetes. Gac seed proteins (GSPs) can hydrolysate used enzymes. Objectives: To investigate the potential of gac seed proteins as a functional food for diabetes treatment based on bioactive peptides. Materials & Methods: The DPPIV inhibitory activities were evaluated using a combination of gastrointestinal proteases. DPPIV inhibitory peptides from GSP hydrolysate were isolated using two sequential bioassay-guided fractions, namely hydrophilic interaction liquid chromatography (HILIC) and reversed-phase high-performance liquid chromatography (RP-HPLC). Peptides in the fraction with the highest DPPIV inhibitory activity were identified using liquid chromatography-mass spectrometry coupled with the de novo sequencing. Results: The DPPIV inhibitory assay showed that GSPs derived from HILIC-70% acetonitrile had the highest activity. Subsequently, this fraction was separated using RP-HPLC, with fraction 6, fraction 8 and fraction 13 each having high DPPIV inhibitory activity, with 10 identified peptides. Their DPPIV inhibitory activities were further predicted using the BIOPEP database in which DSGL had the highest activity. The molecular docking simulation suggested that the DPPIV inhibitory activities of DSGL could be due to its interaction with key residues in the S2 (Glu205, Arg125) pocket and the catalytic residues in the S1 (Ser630, His740) pocket of DPPIV. Main finding: GSP hydrolysate showed potential for drug application or as a functional food additive.