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Research Project: Prevention of Obesity Related Metabolic Diseases by Bioactive Components of Food Processing Waste Byproducts and Mitigation of Food Allergies

Location: Healthy Processed Foods Research

Title: Collagen peptides with DPP-IV inhibitory activity from sheep skin and their stability to in vitro gastrointestinal digestion

item WANG, BEIBEI - Jiangnan University
item ZHE, YU - Jiangnan University
item Yokoyama, Wallace - Wally
item Chiou, Bor-Sen
item CHEN, MAOSHEN - Jiangnan University
item LUI, FEI - Jiangnan University
item ZHONG, FANG - Jiangnan University

Submitted to: Food and Function
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/22/2021
Publication Date: 6/1/2021
Citation: Wang, B., Zhe, Y., Yokoyama, W.H., Chiou, B., Chen, M., Lui, F., Zhong, F. 2021. Collagen peptides with DPP-IV inhibitory activity from sheep skin and their stability to in vitro gastrointestinal digestion. Food and Function. 42. Article 101161.

Interpretive Summary: Type II diabetes has reached alarming levels in developed and some developing countries. Type II Diabetes often accompanies obesity. Glucose metabolism is impaired in both Type II diabetes and insulin resistance states in obesity. GLP-1 is a hormone that reduces blood glucose and stimulates insulin release. It is rapidly degraded by a enzyme, DPP-IV. Peptides containing the amino acid proline have been shown to inhibit the activity of DPP-IV. Collagen a protein in skin is high in proline and its hydrolysis yields proline rich peptides. This research evaluated the potential of a waste product, sheepskin, to produce DPP-IV inhibitors. The peptide products of several enzyme treatments were identified by HPLC/MS and also from computer simulations based on the genetic code of sheep skin protein. Good candidates were synthesized and tested for their DPP-IV activity.

Technical Abstract: Collagen is a potential precursor protein for dipeptidyl peptidase-IV (DPP-IV) inhibitory peptides due to its high content of proline (Pro). Collagen peptides with DPP-IV inhibitory activity were prepared and identified from sheep skin. The peptide sequences with the highest potential for DPP-IV inhibition were identified by nano LS-MS/MS and in silico analysis. DPP-IV inhibitory activity of collagen peptides usually decreased after digestion, therefore the effect of peptides digestion on DPP-IV inhibitory activity were studied. Four DPP-IV inhibitory activity peptides resistant to digestive enzymes or having the possibility of generating new peptides with DPP-IV inhibitory activity after digestion were synthesized. The activity of synthetic peptides before and after digestion were also studied. GPAGPIGPV was resistant to digestion and GPAGPOGFPG released DPP-IV inhibitory peptides in silico digestion, suggesting that they can maintain high DPP-IV inhibitory activity after digestion. Binding sites of the peptides with DPP-IV were investigated by molecular docking simulation, indicating the mechanism of the peptide having DPP-IV inhibitory activity. The results suggested that the DPP-IV-inhibitory peptides identified from sheep skin collagen may be potential functional components in the diabetic diet.