iodoacetic acid - site C 58.0054779052734375 58.04000091552734375 C C 2 H 2 O 2 Carboxymethyl Iodoacetic acid derivative MOD:01061 MOD:01329 Modification from Unimod Chemical derivative, Unimod:6 site C OBSOLETE because duplicate and redundant with MOD:01061. Remap to MOD:01061 PSI-MOD Unimod:6 artifact true