Preparation, receptors, bioactivity and bioavailability of γ-glutamyl peptides: A comprehensive review

Background: The gamma-glutamyl peptides refer to a series of bioactive peptides containing gamma-glutamyl residues. The unique gamma-glutamyl linkage endows gamma-glutamyl peptides with higher in vivo stability and longer half-life, which contributes to their potent physiological functions. Recently, gamma-glutamyl peptides have become the focus of researchers due to the unique Kokumi taste and various potential bioactivities mediated through activation of the calcium-sensing receptor (CaSR). However, review articles on the emerging bioactivities and potential mechanisms responsible for intestinal absorption of gamma-glutamyl peptides are very scanty. Scope and approach: This article aimed to discuss the significance and role of gamma-glutamyl peptides in human health. The present review systematically summarizes the available scientific information on the preparation, CaSR, bioactivity and bioavailability of food-derived gamma-glutamyl peptides. Furthermore, the current scientific challenges and future research directions are also discussed. Key findings and conclusions: gamma-Glutamyl peptides have been reported to exhibit diverse bioactivities, including anti-inflammatory, hypoglycemic and appetite-suppressing effects as well as the ameliorating effect on colon health, which are attributed to CaSR activation. Moreover, due to the high resistance towards gastrointestinal digestion, gamma-glutamyl peptides can play a key role in the gastrointestinal tract and also be transported across the intestinal epithelium mainly via peptide transporter 1 (PepT1) or paracellular routes to exhibit various in vivo activities. In addition, further and intensive investigations are urgently required to address the current challenges pertaining to the effective preparation, novel physiological functions and exact absorption mechanisms of gamma-glutamyl peptides. This review contributes to a better understanding of gamma-glutamyl peptides in terms of their cellular receptor, bioactivity and bioavailability.

Automated summary

Gamma-glutamyl peptides, with their unique characteristics, play an important role in human health and exhibit diverse bioactivities mainly through CaSR activation. Due to their stability and resistance to digestion, they can exert various in vivo activities via different absorption routes in the gastrointestinal tract. Further research is needed to address challenges in preparation, physiological functions, and absorption mechanisms of these peptides.