2-pyrrolidone-5-carboxylic acid (Gln) (2S)-5-oxo-2-pyrrolidinecarboxylic acid -17.026548385620117188 -17.030000686645507812 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-glutamine residue to 2-pyrrolidone-5-carboxylic acid. C 0 H -3 N -1 O 0 C 5 H 6 N 1 O 2 DeltaMass gives a formula C 5 H 5 N 1 O 2 with mass 111.1 Gln->pyro-Glu MOD:00040 MOD_RES Pyrrolidone carboxylic acid N-pyrrolidone carboxyl (N terminus) N-term PCA PSI-MOD PyrGlu(Gln) Pyro-glu from Q Pyroglutamic Acid formed from Gln Pyroglutamyl Q Unimod:28 natural ntermpeppyroq pyroglutamic acid uniprot.ptm:PTM-0261 modified L-glutamine residue 2-pyrrolidone-5-carboxylic acid deaminated residue