Exploring dipeptidyl peptidase‐IV inhibitory peptides from Tartary Buckwheat protein: A study of hydrolysis, fractionation, and molecular interactions

Abstract Tartary buckwheat, a protein‐rich pseudocereal with anti‐diabetic effects, has not yet been fully explored as a source of dipeptidyl peptidase‐IV (DPP‐IV) inhibitory peptides. This study aims to discover novel DPP‐IV inhibitory peptides from tartary buckwheat protein (TBP). Five hydrolysis methods were employed, with simulated gastrointestinal digestion (SGID) releasing the most active DPP‐IV inhibitory hydrolysates, showing both the highest degree of hydrolysis (22.66 ± 1.12%) and inhibition activity (41.81 ± 1.52% at 1.25 mg/mL). In addition, ultrafiltration enriched the <3 kDa fraction with the highest inhibitory rate, and further purification using reverse‐phase high‐performance liquid chromatography concentrated the DPP‐IV inhibitory peptides in the first fraction (F1). Nano liquid chromatography‐tandem mass spectrometry analysis identified 10 new peptides in F1, among which the peptide Leu‐His‐Ile‐Val‐Gly‐Pro‐Asp‐Lys (LHIVGPDK) exhibited the strongest inhibitory effect, with an IC 50 value of 1.61 mM. Kinetic studies revealed that LHIVGPDK acts as a mixed‐type inhibitor, and molecular docking indicated that it inhibits DPP‐IV by forming stable complexes through five types of interactions, with hydrogen bonds playing a key role. This study underscores TBP's DPP‐IV inhibitory potential and anti‐diabetic properties, reinforcing the value of tartary buckwheat as a beneficial food for diabetes management. Practical Application This research identified new peptides from Tartary buckwheat protein that effectively inhibit DPP‐IV, an enzyme associated with diabetes management. These findings suggest potential applications in developing functional foods to help control hypoglycemia.