Trypsin edta

Potassium ferricianyde, ferrous sulfate II, trichloroacetic acid, and sulfuric acid were purchased from Merck (Darmstadt, Germany). Nitro Blue Tetrazolium (NBT), monosaccharides, diaminoethanetetraacetic acid (EDTA), ascorbic acid, methionine, 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT), Griess reagent, pyrocatechol violet, riboflavin, and ammonium molybdate were purchased from Sigma-Aldrich Co. (St. Louis, MO, USA). Sodium bicarbonate, non-essential amino acids, and phosphate buffered saline (PBS) were purchased from Invitrogen Corporation (Burlington, ON, Canada). Dulbecco′s modified Eagle′s medium (DMEM) and fetal bovine serum (FBS) were obtained from CULTILAB (Campinas, SP, Brazil). Penicillin and streptomycin were obtained from Gibco (Fort Worth, TX, USA). All other solvents and chemicals were of analytical grade.
The HEK-293 cells (ATCC^® CRL-1573™) were grown in a DMEM medium with 10% FBS, 100 μg/mL streptomycin and 100 IU/mL Penicillin. The cells were cultured in DMEM supplemented with FBS (10% v/v) and antibiotics (100 U/mL Penicillin and 100 μg/mL streptomycin), at 37 °C in a humidified atmosphere with 5% CO₂. For maintenance of the cells, the culture medium was changed every three days, and the cells were further subcultured using trypsin/EDTA purchased from CULTILAB (Campinas, SP, Brazil).