derives from alpha-amino propanoylated residue alpha-amino 3x(13)C-labeled propanoylated residue (12)C 6 (13)C 3 H 16 N 2 O 2 (13)C 3 H 4 O 1 187.1300048828125 187.1312408447265625 59.03627777099609375 59.04000091552734375 A protein modification that effectively replaces a residue alpha-amino- or alpha-imino-hydrogen with a 3x(13)C-labeled propanoyl group. MOD:00452 N-term PSI-MOD Propionate labeling reagent heavy form (+3amu), N-term & K Propionyl:13C(3) Unimod:59 X artifact isotope tagged reagent derivatized residue (13)C isotope tagged reagent