Symmetric di methyl arginine

Anti-methyl lysine or tyrosine antibodies (PTM-SCAN antibodies, pan-methyl lysine, mono-methyl arginine, symmetric di-methyl arginine, asymmetric di-methyl arginine, di-methyl lysine, and mono-methyl lysine) were purchased from Cell Signaling Technology (Danvers, MA, USA). The SILAC amino acids L-lysine (13C615N2, Cat# CNLM-291-632) and L-arginine (13C615N4, Cat# CNLM-539-H-1) were purchased from Cambridge Isotope Laboratories Inc., Cambridge, MA, USA. Trypsin treated with TPCK was obtained from Worthington Biochemical Co. (Lakewood, NJ, USA). Regular DMEM and DMEM deficient in L-lysine or L-arginine were obtained from Thermo Scientific. Fetal bovine serum (FBS), antibiotics, and phosphate-buffered saline (PBS, pH7.4) were obtained from Invitrogen (Carlsbad, CA, USA). Iodoacetamide and DL-dithiothreitol were purchased from Sigma–Aldrich (Burlignton, MA, USA).