N-terminal [Glu]3 moiety of γ-glutamyl peptides contributes largely to the activation of human calcium-sensing receptor, a kokumi receptor

gamma-glutamyl peptides have been suggested to impart kokumi properties to foods by activating human calcium-sensing receptor (hCaSR). In this study, the relationship between gamma-glutamyl peptide structure and hCaSR activity was systematically analyzed using gamma-[Glu]((n=0-4))-alpha-[Glu]((n=0-3))-Tyr. Our results suggest that N-terminal [Glu](3) moiety is very important for hCaSR activities of gamma-glutamyl peptides.