4x(2)H labeled dimethylated residue 4x(2)H labeled alpha-dimethylamino N-terminal residue 32.056407928466796875 32.060001373291015625 A protein modification that effectively converts an N-terminal residue to an 4x(2)H labeled alpha-dimethylamino N-terminal residue. C 2 (2)H 4 DiMethyl-CHD2 Dimethyl:2H(4) MOD:01459 N-term PSI-MOD Supposed to be alpha-amino and Lys-N6 derivatized by C(2)H2O and reduction. Unimod:199 X artifact mod190