Dipeptidyl peptidase IV inhibitory properties of a whey protein hydrolysate: Influence of fractionation, stability to simulated gastrointestinal digestion and food-drug interaction

Alice B. Nongonierma, Richard J. FitzGerald

Research output: Contribution to journalArticlepeer-review

Abstract

The invitro dipeptidyl peptidase IV (DPP-IV) inhibitory activity of a whey protein hydrolysate (WPH) generated with a food-grade pancreatic enzyme preparation was studied. The 50% inhibitory concentration (IC50) value in the presence of WPH was 1.34±0.11mgmL-1. Ultrafiltration (UF) fractionation of WPH allowed enrichment in DPP-IV inhibitory peptides. The permeates generated by UF through 5 and 2kDa membranes along with the hydrophilic fraction isolated by solid-phase extraction were significantly more potent DPP-IV inhibitors than WPH. Simulated gastrointestinal digestion of WPH resulted in an increased DPP-IV inhibitory potency (IC50 value of 1.02±0.05mgmL-1). Competitive inhibition of DPP-IV was observed with WPH and all its fractions, indicating a direct interaction of the bioactive peptides therein with the active site of DPP-IV. Combinations of sitagliptin, a conventional drug-inhibitor of DPP-IV, and whey-derived peptides resulted in an additive effect on DPP-IV inhibition.

Original languageEnglish
Pages (from-to)33-39
Number of pages7
JournalInternational Dairy Journal
Volume32
Issue number1
DOIs
Publication statusPublished - Sep 2013

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