6x(13)C,4x(15)N labeled L-arginine (12)C -6 (13)C 6 (14)N -4 (15)N 4 (13)C 6 H 12 (15)N 4 O 1 10.008269309997558594 10.010000228881835938 13C(6) 15N(4) Silac label 166.109375 166.1100006103515625 A protein modification that effectively converts an L-arginine residue to 6x(13)C, 4x(15)N labeled L-arginine. Label:13C(6)15N(4) MOD:00587 PSI-MOD R Unimod:267 arg-13c6-15n4 artifact (13)C labeled residue (15)N labeled residue modified L-arginine residue