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MB Sample ID: SA164174

Local Sample ID:blank2
Subject ID:SU001837
Subject Type:Mammal
Subject Species:Mus musculus
Taxonomy ID:10090

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Sample Preparation:

Sampleprep ID:SP001843
Sampleprep Summary:Metabolites were quenched as quickly as possible while working with the samples at low temperatures. Cells were handled at 4ºC or on dry ice, extraction buffer was pre-chilled at -20ºC. Samples were analyzed by LC-MS on the same day of extraction (if impractical, best alternative is to store dried samples at -80ºC). Unless indicated otherwise, 1 million cells or about 2 mg of tissue was extracted per condition and a minimum of three replicates per condition was used in each experiment. K562 cells that are non-adherent, were collected by brief centrifugation at 4ºC using a table-top centrifuge (4,500 rpm, 1.5 min) and washed briefly in 0.9% NaCl (high grade salt and LC-MS-grade water Fisher Scientific W6500 or Sigma Aldrich 1.15333). 300 µl of prechilled extraction buffer were added per sample. For tissues – chunks were crushed using a hand-held homogenizer (VWR 47747-370) with several pulses while keeping the samples on ice. 300 µl of prechilled extraction buffer was used per 2 mg of tissue. Extraction buffer “A”: 40:40:20 of acetonitrile:methanol:water, supplemented with 0.1M formic acid and isotopically-labeled internal standards (17 amino acids and reduced glutathione, Cambridge Isotope Laboratories, MSK-A2-1.2 and CNLM-6245-10). Extraction buffer “B”: 80% LC-MS-grade methanol, 20% 25 mM Ammonium Acetate and 2.5 mM Na-Ascorbate prepared in LC-MS water and supplemented with isotopically labeled internal standards (17 amino acids and isotopically labelled reduced glutathione, Cambridge Isotope Laboratories, MSK-A2-1.2 and CNLM-6245-10). Extraction buffer “C” and “C + Ellman’s”: Solution 1: 100% LC-MS Methanol Solution 2: 25mM Ammonium Acetate and 2.5mM Na-Ascorbate in LC-MS water supplemented with isotopically labelled reduced glutathione and isotopically labeled internal standards (17 amino acids and reduced glutathione, Cambridge Isotope Laboratories, MSK-A2-1.2 and CNLM-6245-10). Ellman’s reagent (5,5′-Dithiobis(2-nitrobenzoic acid),D8130, Sigma Aldrich): 20 mM in “Solution 2”. Final composition is 80% solution 1 and 20% solution 2. Samples were vortexed briefly (10 sec) and sonicated for 3 min in a 4ºC water bath. Samples were then centrifuged for 10 min, 4ºC, at maximum speed on a benchtop centrifuge (Eppendorf) and the cleared supernatant was transferred to a new tube. Samples were dried using a nitrogen dryer while on ice, and special attention was given to minimize the time of drying and to not let samples idle in the dryer (Reacti-Vap™ Evaporator, Thermo Fisher Scientific, TS-18826) once the drying process was completed. Needles were continuously adjusted to the surface of the liquid as the samples evaporated to expedite the drying process. Samples were reconstituted in 30 µl LC-MS-grade water by brief sonication in a 4ºC water bath. Extracted metabolites were spun for 2 min at maximum speed on a bench-top centrifuge and cleared supernatant was transferred to LC-MS micro vials (National Scientific, C5000-45B). A small amount of each sample was pooled and serially diluted 3- and 10-fold to be used as quality controls throughout the run of each batch.
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