Ac-Lys-Asp-Ser-Phe-Val-Gly-
L-lysyl-L-α-aspartyl-L-seryl-L-phenylalanyl-L-valyl-(αS,3R)-3-amino-α-(2-methylpropyl)-2-oxo-1-pyrrolidineacetyl-L-methioninamide
(R)-2-<3-<(tert-butoxycarbonyl)amino>-2-oxo-1-pyrrolidinyl>-(S)-4-methylpentanoic acid pentafluorophenyl ester
(2S)-2-<(3R)-3-<(tert-butoxycarbonyl)amino>-2-oxopyrrolidin-1-yl>-4-methylpentanoic acid