Methoxyamine hydrochloride

Paraformaldehyde (PFA), phosphate buffer, phosphate buffer saline, ethylene glycol, glycerol, sucrose, hydrogen peroxide, 3,3′-diaminobenzidine, methanol, methoxyamine hydrochloride, N-methyl-N-(trimethylsilyl) trifluoroacetamide, anti-tyrosine hydroxylase (TH) antibody (AB152), skim milk and polyvinylidene fluoride (PVDF) membrane were purchased from Merck Millipore (Burlington, MA, United States). Anti-α-syn antibody (610787) was purchased from BD biosciences (Franklin Lakes, NJ, United States). Goat anti-mouse HRP secondary antibody (ADI-SAB-100) was purchased from Enzo life sciences (Farmingdale, NY, United States). Goat anti-Mouse Secondary antibody (Alexa Fluor 488, A-11001) was purchased from Invitrogen (Waltham, MA, United States). Biotinylated goat anti-rabbit IgG antibody (BA-1000), avidin-biotin complex and Goat anti-Rabbit Secondary antibody (DyLight Fluor 594, DI-1594) were purchased from Vector Laboratories (Burlingame, CA, United States).

The following reagents were acquired from Sigma Aldrich (St. Louis, Missouri, USA) and Merck (Darmstadt, Germany): 3-phenylbutyric acid, methoxyamine hydrochloride (MOX-HCl), anhydrous sodium sulphate (Na₂SO₄), urease, glucose, 4-aminobutyric acid (GABA), L-alanine, L-leucine, L-phenylalanine, L-tryptophan, L-tyrosine, ascorbic acid, citric acid, succinic acid, palmitic acid, arabinose, ribose, N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) with 1% trimethylsilyl chloride (TMCS), and pyridine. Other chemicals used were acetonitrile, ethyl acetate, hydrogen chloride and diethyl ether from Burdick and Jackson brand (Honeywell International Inc., Muskegon, USA).

Methoxyamine hydrochloride (quality level: MQ 200) was purchased from Merck (Darmstadt, Germany). Pyridine (extra dry) (99.5+% evaluated by capillary GC), acetone (Dioxins Analysis Grade, purity 99.8%), and d₁₀-phenanthrene (Environment Analysis Grade, purity 99.5%) were obtained from Wako Chemicals Ltd. (Osaka, Japan). The metabolite mixture kit for GC/MS-based metabolomics and N-methyl-N-(trimethylsilyl trifluoroacetamide) (MSTFA) were purchased from GL Sciences Inc. (Tokyo, Japan). Acetonitrile (LC-MS grade) and methanol (LC-MS grade) were purchased from Kanto Chemical (Tokyo, Japan). Standard Reference Material (SRM) 1950 “Metabolites in Human Plasma” was obtained from the National Institute of Standards and Technology (NIST, Gaithersburg, MD). Adipic acid (purity 99.5%), chloroform (purity 99.0%), and methanol (purity 99.8%) were obtained from Nacalai Tesque Inc. (Kyoto, Japan).

¹³C₃-lactic acid, ¹³C₂-oxalic acid, ²H₃-sacrosine, ²H₈-valine, ¹³C₃-dihydroxyacetone, ²H₁₀-isoleucine, ¹³C₄-fumaric acid, ¹³C₄-malic acid, ²H₃-aspartic acid, ¹³C₅-glutamic acid, ¹³C₆-4-hydroxybenzoic acid, ²H₃-lauric acid, ¹³C₅-ribose, ¹³C₂-taurine, ²H₄-citric acid, ²H₇-ornithine, ¹³C₆-tyrosine, ¹³C₆-dopa, ²H₆-kynurenine, ²H₈-cystamine, and ¹³C₁₁-tryptophan were purchased from Cambridge Isotope Laboratories, Inc. (MA, USA). ²H₃-2-hydorxybutyric acid and 2-isopropylmalic acid were purchased from CDN isotopes (Quebec, CA) and Sigma Aldrich (Tokyo, Japan), respectively. The compounds were dissolved in methanol, as shown in Supplementary Table 3, and then the obtained solution was used as an extraction solution. A standard alkane series mixture (C7 to C33) and octafluoronaphthalene (OFN) were purchased from Restek Co. (PA, USA) and Shimadzu Co. (Kyoto, Japan), respectively. Methoxyamine hydrochloride and N-methyl-N-trimethylsilyl-trifluoroacetamide (MSTFA), which were used for the derivatization, were obtained from Sigma-Aldrich and GL Science (Tokyo, Japan), respectively.