Glutathione reduced form

2,2′-Azobis(2-methyl-propionamidine) dihydrochloride (AAPH), copper sulphate, Chelex® 100 sodium, quercetin, thiobarbituric acid, trichloroacetic acid, Amberlite XAD-7, sodium bicarbonate, methylglyoxal, glutathione (reduced form), 1-chloro-2,4-dinitrobenzene (CDNB), L-glutamine, and CelLytic™ M were purchased from Sigma-Aldrich (St. Louis, MO, USA). Pierce™ BCA Protein Assay Kit was obtained from Thermo Scientific (Rockford, IL, USA). Hydrogen peroxide (30%), HCl, methanol, and formic acid were purchased from Merck (Darmstadt, Germany). MTT was obtained from Calbiochem (Darmstadt, Germany). Fetal bovine serum (FBS), antibiotics, and culture media were purchased from Invitrogen (Grand Island, New York, USA). Ultrapure water was obtained using a Barnstead EasyPure water filter system (Thermo Scientific, Dubuque, IA, USA).

3-HK, KYN, KYNA, Trp, glutathione reduced form (GSH), oxidized glutathione (GSSG), N-ethylmaleimide (NEM), O-phthaldialdehyde (OPA), thiobarbituric acid (TBA) and trichloroacetic acid (TCA) were obtained from Sigma-Aldrich (St. Louis, MO, USA). All other chemicals were of the highest commercially available purity. Solutions were prepared using deionized water.