Agilent 1200 series isocratic hplc pump

All stable isotopes were purchased from Cambridge Isotope Laboratories, Inc. Cells were seeded on a 100 mm dish and cultured overnight. On the next day, culture media were replaced to [U-¹³C] glucose containing culture media (DMEM/10% FBS/4.5 g/L [U-¹³C] glucose for U87MG, MEM/10% HS/1 g/L [U-¹³C] glucose for primary glia) or ¹⁵N₅-guanosine-containing culture media (DMEM/10% dialyzed FBS or MEM/10% HS/1 μM guanosine). For neurospheres, neural stem cell-supporting culture medium (NSM) containing 17.5 mM [U-¹³C] glucose, 2.5 mM ¹³C₅, ¹⁵N₂-glutamine was used. Cells were harvested at indicated times. Extraction of metabolites was performed as previously described⁶² . Capillary electrophoresis-time-of-flight mass spectrometry (CE-TOFMS) experiments were performed using an Agilent G7100A Capillary Electrophoresis instrument (Agilent technologies), an Agilent 6224 TOF LC/MS system (Agilent technologies), an Agilent 1200 series isocratic HPLC pump, a G1603A Agilent CE-MS adapter kit and a G1607A Agilent CE-electrospray ionization (ESI)-MS sprayer kit. For CE-TOFMS system control and data acquisition, we used an Agilent MassHunter software. Detailed conditions of CE-TOFMS-based metabolome analysis were described^{63 ,64} . Capillary ion chromatography (IC)-MS analysis was performed using a Dionex ICS-5000⁺ system equipped with a Q Exactive Orbitrap MS system (Thermo Fisher Scientific).