O-acetyl-L-serine 129.0425872802734375 129.1100006103515625 42.01056671142578125 42.04000091552734375 Acetylation MOD:00369 OAcSer incidental to RESID:AA0051 O-acetylserine A protein modification that effectively converts an L-serine residue to O-acetyl-L-serine. S (2S)-3-(acetyloxy)-2-aminopropanoic acid PSI-MOD serine acetate ester none C 5 H 7 N 1 O 3 O-acetylated L-serine Acetyl O-acetyl-L-serine C 2 H 2 O 1 MOD_RES O-acetylserine natural mono O-acetylated residue monoacetylated L-serine O3-acylated L-serine