Isolation and identification of dipeptidyl peptidase‐IV inhibitory peptides from Sacha inchi meal

Abstract

BACKGROUND Sacha inchi meal (SIM) is a by‐product of oil processing. Our previous studies showed that SIM hydrolysates exhibited dipeptidyl peptidase‐IV (DPP‐IV) inhibition activity. The objective of the present work was to identify and characterize the bioactive peptides from protein hydrolysates of SIM; enzyme kinetics and peptide–enzyme interaction were also investigated. RESULTS From SIM hydrolysates, ten peptides responsible for the activity were identified: GPSRGF (GF‐6), FPILSPDPA (FA‐9), APYRRGGKI (AI‐9), WPYH (WH‐4), DPATWLALPT (DT‐10), NPEDEFRQQ (NQ‐9), APESKPVGV (AV‐9), LEWRDR (LR‐6), APVYWVQ (AQ‐7) and LLMWPY (LY‐6). The IC50 values of five peptides (GF‐6, WH‐4, AQ‐7, AV‐9 and LY‐6) with better inhibitory activity on DPP‐IV were within the range of 23.43–128.40 μmol L−1. AQ‐7 had the best activity, with an IC50 value of 23.43 μmol L−1. Enzyme kinetics indicated the presence of various inhibition types (mixed, non‐competitive and competitive). Isothermal titration microcalorimetry showed that the main forces of the binding sites between peptide (GF‐6 or AQ‐7) and DPP‐IV were hydrogen bond, hydrophobic interaction and van der Waals force. The key residues involved in peptide–enzyme interaction were determined by molecular docking. Furthermore, at a concentration of 800 μmol L−1, GF‐6 was found to significantly increase the glucose consumption in insulin‐resistant HepG2 cells (P < 0.05) compared with the model group. CONCLUSION Sacha inchi meal‐derived peptides displayed potent DPP‐IV inhibition activity and could be used in the health food industry and as lead compounds for diabetes therapy. © 2023 Society of Chemical Industry.

DPP-IV Inhibitory Peptides from Coix Seed Prolamins: Release, Identification, and Analysis of the Interaction between Key Residues and Enzyme Domains

“…It was suggested that an interaction occurred between the three coix seed prolamin-derived inhibitory peptides and DPP-IV. Hydrogen bonding or conjugation occurred between the two, resulting in a wider range of electron activities during the energy jump with the main absorption peaks moving in the long-wave direction . The binding constants K A of 9.16 × 10 3 , 4.50 × 10 4 , and 5.81 × 10 4 mol/L were calculated by fitting the Lineweaver–Burk double inverse curve plot (Figure D) of LPFYPN, TFFPQ, and ATFFPQ interacting with DPP-IV, respectively.…”

“…This assay was performed following the methods described by Zhang et al DPP-IV was diluted to 0.03 U/mL in a Tris–HCl buffer (100 mM, pH 8.0). DPP-IV (1 mL) was gradually added to different concentrations of the peptide solution (Q, 10 μL), and the mixture was equilibrated for 5 min.…”

Evaluating the Potential of Plukenetia volubilis Linneo (Sacha Inchi) in Alleviating Cardiovascular Disease Risk Factors: A Mini Review

“…The potent α-glucosidase and α-amylase inhibitory effects are linked to the phenolic content in SI [87][88][89][90]. Furthermore, SI meal-derived peptides demonstrated potent DPP-IV inhibitory activity in vitro, which was further validated with increased glucose consumption by palmitic acid-induced insulin resistant HepG2 cells [91]. It is important to emphasize that α-amylase, α-glucosidase, and DPP-IV inhibitory assays serve as valuable screening tools to evaluate the antidiabetic potential of natural products.…”