2-pyrrolidone-5-carboxylic acid (Glu) (2S)-5-oxo-2-pyrrolidinecarboxylic acid -18.010564804077148438 -18.020000457763671875 112.03985595703125 112.1100006103515625 2-oxopyrrolidine-5-carboxylic acid 2-pyrrolidone-5-carboxylic acid 5-oxoproline 5-oxopyrrolidine-2-carboxylic acid 5-pyrrolidone-2-carboxylic acid A protein modification that effectively converts an L-glutamic acid residue to 2-pyrrolidone-5-carboxylic acid. C 0 H -2 N 0 O -1 C 5 H 6 N 1 O 2 E From DeltaMass: References: The conversion of glutamic acid to pyroglutamic was reported for the beta-amyloid protein. Miller et al. Arch. Biochem. Biophy. (1993) 301, 41-52 [DeltaMass]. The modification in amyloid protein is probably an artifact of treatment with strong acid under anhydrous conditions. Peptides with N-terminal glutamic acid isolated from single cells of Aplysia neurons show partial conversion to pyroglutamic acid, possibly dependent on a temperature sensitive factor [JSG]. Glu->pyro-Glu MOD:00420 MOD_RES Pyrrolidone carboxylic acid (Glu) N-term PCA PSI-MOD PyrGlu(Glu) Pyro-glu from E Pyroglutamic Acid formed from Glutamic Acid Unimod:27 artifact ntermpeppyroe pyroglutamic acid uniprot.ptm:PTM-0262 modified L-glutamic acid residue 2-pyrrolidone-5-carboxylic acid