(13)C labeled residue (15)N labeled residue 6x(13)C,1x(15)N labeled residue (12)C -6 (13)C 6 (14)N -1 (15)N 1 13C(6) 15N(1) Silac label 7.0171642303466796875 7.0199999809265136719 A protein modification that effectively converts a residue containing common isotopes to a 6x(13)C,1x(15)N labeled residue. Label:13C(6)15N(1) MOD:01370 PSI-MOD Unimod:695 X artifact