91856-42-7 Glycine, N-(N-(N-(5-oxo-L-prolyl)-L-alpha-glutamyl)-L-alpha-aspartyl)-, (3aS-(3aalpha,4beta,6aalpha))- Pglu-glu-asp-glyoh Pyroglu-glu-asp-gly-OH Pyroglutamyl-glutamyl-asparaginyl-glycine