Purification and characterization of the dipeptidyl peptidase‐IV inhibitory peptides from eel (Anguilla rostrata) scraps enzymatic hydrolysate for the treatment of type 2 diabetes mellitus

• Published in: Journal of the science of food and agriculture 2023-05, Vol.103 (7), p.3714-3724
• Main Authors: Cao, Hongzhen, Di, Nana, Jiang, Bo, Chen, Jingjing, Zhang, Tao
• Format: Article
• Language: English
• Subjects: Amino acids; Anguilla - metabolism; Anguilla rostrata; Animals; Chromatography; Diabetes; Diabetes mellitus; Diabetes mellitus (non-insulin dependent); Diabetes Mellitus, Type 2 - drug therapy; Diabetes Mellitus, Type 2 - veterinary; Dipeptidyl Peptidase 4 - chemistry; Dipeptidyl-Peptidase IV Inhibitors - chemistry; DPP‐IV inhibitory peptides; eel (Anguilla rostrata) scraps; Functional foods & nutraceuticals; Gel filtration; Health risks; High performance liquid chromatography; Humans; Hydrogen bonding; Hydrogen bonds; Hydrolysates; hydrolysis; Insulin; Insulin secretion; Ionization; Ions; Liquid chromatography; Mass spectrometry; Mass spectroscopy; Molecular docking; Molecular Docking Simulation; Peptidase; Peptidases; Peptides; Peptides - chemistry; Protein purification; Proteins; purification; Scientific imaging; Secretion; Synthetic peptides; T2DM; Tandem Mass Spectrometry; Ultrafiltration
• ISSN: 0022-5142; 1097-0010
• DOI: 10.1002/jsfa.12462

BACKGROUND Type 2 diabetes mellitus (T2DM) is a serious threat to human health. Owing to the action of dipeptidyl peptidase‐IV (DPP‐IV), the half‐life of entero‐insulin hormone after secretion is extremely short, causing insufficient insulin secretion in diabetic patients. Dipeptidyl peptidase‐IV inhibitors can be used as a new treatment for T2DM. In this study, the proteins of eel (Anguilla rostrata) scraps hydrolyzed using Protamex protease (EPHs) were found to have strong DPP‐IV inhibitory activity. The study also provided research ideas for the development and utilization of A. rostrata scraps. RESULTS The median inhibition concentration (IC50) value of EPHs was 5.455 ± 0.24 mg mL−1. The peptide fractions with the highest DPP‐IV inhibitory activity were sequentially separated by ultrafiltration, gel filtration chromatography (GFC), and reversed‐phase high performance liquid chromatography (RP‐HPLC) in a continuous hierarchical manner and analyzed using matrix‐assisted laser desorption/ionization time‐of‐flight/ time‐of‐flight mass spectrometry/mass spectrometry (MALDI‐TOF/TOF MS/MS). Three peptides that revealed significant inhibitory activity were screened among the identified sequences, with sequences of Phe‐Pro‐Arg (IC50 = 62.14 ± 1.47 μM), Tyr‐Pro‐Pro‐Ser‐Phe‐Ser (IC50 = 102.65 ± 4.57 μM), and Tyr‐Pro‐Tyr‐Pro‐Ala‐Ser (IC50 = 68.30 ± 3.85 μM). Molecular docking simulations revealed that their inhibitory effect was mainly due to the formation of hydrogen bonds with amino acid residues in the active sites of DPP‐IV. Analysis of the inhibition patterns of the synthetic peptides displayed that Phe‐Pro‐Arg and Tyr‐Pro‐Pro‐Ser‐Phe‐Ser displayed competitive inhibition, whereas Tyr‐Pro‐Tyr‐Pro‐Ala‐Ser showed mixed competitive/non‐competitive inhibition. CONCLUSIONS The protein hydrolysates isolated from eel scraps are potential functional food ingredients for the treatment of T2DM. © 2023 Society of Chemical Industry.