Inhibition mechanism of oligopeptides from soft‐shelled turtle egg against α‐glucosidase and their gastrointestinal digestive properties. Issue 10 (27th July 2022)

• Record Type: Journal Article
• Authors: Li, Nan; Qiu, Leyun; Song, Hailing; Xiao, Ting; Luo, Ting; Deng, Zeyuan; Zheng, Liufeng
• Is Part Of: Journal of food biochemistry. Volume 46:Issue 10(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-07-27
• Subjects: gastrointestinal digestive properties -- inhibition mechanism -- molecular docking -- soft‐shelled turtle egg -- α‐glucosidase inhibitory oligopeptides; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; Biochemistry -- Periodicals; 664.024
• DOI: 10.1111/jfbc.14328
• Languages: English
• ISSNs: 0145-8884

Abstract

Abstract: Peptides derived from egg protein hydrolysate have potential hypoglycemic benefits by inhibiting α‐glucosidase. Herein, fluorescence spectroscopy and molecular docking were performed to investigate the α‐glucosidase inhibitory mechanism of the oligopeptides ARDASVLK and HNKPEVEVR from soft‐shelled turtle eggs. Gastrointestinal digestion characteristics of the two oligopeptides were further determined by LC‐QTOF‐MS/MS. The static fluorescence quenching of α‐glucosidase by ARDASVLK and HNKPEVEVR indicated the formation of a stable α‐glucosidase‐peptide complex, mainly driven by hydrogen bonds and hydrophobic interactions. ARDASVLK and HNKPEVEVR could easily insert into the active pocket of α‐glucosidase (docking scores of −157.1 and −158.4, respectively), thereby inhibiting enzyme activity by preventing substrate binding and inducing enzymatic conformation change. After gastrointestinal digestion, 14.3% and 30.4% of ARDASVLK and HNKPEVEVR were maintained intact, respectively, and their digestive products (mainly DASVLK and HNKPEVEV) still showed high inhibitory effects on α‐glucosidase (about 35% inhibition). This study sheds light on the mechanism of oligopeptides derived from soft‐shelled turtle eggs as a novel α‐glucosidase inhibitor for diabetes. Practical applications: Oligopeptides from egg protein hydrolysate have potential hypoglycemic properties by inhibiting α‐glucosidase. This study has provided insights into the inhibitory mechanism of oligopeptides from soft‐shelled turtle egg on α‐glucosidase. Interestingly, despite the fact that the oligopeptides are largely degraded during gastrointestinal digestion, their digestive metabolites displayed strong α‐glucosidase inhibitory activities. Because α‐glucosidase is highly expressed in small intestine brush border, our findings support the possibility of these oligopeptides as an attractive health‐benefit compound to control glucose without being absorbed by intestinal epithelial cells, unlike other enzyme inhibitors such as ACE inhibitors, which have poor oral bioavailability. This study may facilitate the applications of oligopeptides from soft‐shelled turtle egg as α‐glucosidase inhibitors and food functional ingredients for the therapy of diabetes. Abstract : The two oligopeptides ARDASVLLK and HNKPEVEVR from soft‐shelled turtle egg can quench α‐glucosidase by forming the α‐glucosidase‐peptide complex, which occupy the active cavity and induce conformation change of the enzyme, and eventually inhibiting enzyme activity. Although ARDASVLK and HNKPEVEVR are degraded after gastrointestinal digestion, their digestive products (mainly DASVLK and HNKPEVEV) still had good α‐glucosidase inhibitory activities.