Blood containing EDTA as an anticoagulant was drawn at different time points and immediately centrifuged. Plasma was subsequently collected and frozen at − 80 °C until analysis. SAM, SAH, choline, d9-choline, betaine, d9-betaine, dimethylglycine (DMG), ethanolamine (EA), sarcosine, d3-sarcosine, methionine, L-homocystine, dithiothreitol (DTT), creatine, d3-creatine, guanidinoacetate (GAA), 13C2-GAA and MMA were obtained from Sigma-Aldrich (Saint Louis, USA). d3-SAM, d6-dimethylglycine, d4-ethanolamine, d3-methionine, and d8-DL-homocystine were purchased from CDN-isotope (Pointe-Claire, Canada). D4-SAHwas bought by cayman chemical (Ann Arbor, USA).
Free choline, ethanolamine, creatine, GAA, and MMA were assayed after deproteinization by an LC–MS/MS method adapted from Holm et al. [19 (link)], Imbard et al. [20 (link)], and Cognat et al. [21 (link)]. The analytical system consisted of an Acuity UPLC I Class system (Waters, Milford, USA) coupled with a Xevo-TQD (Waters, Milford, USA) with an Atlantis HILIC analytical column (2.1 × 100 mm, 3 µm) (Waters, Milford, USA).
SAM, SAH, tHcy, Met, betaine, DMG, and sarcosine were measured using new LC–MS/MS developed in our laboratory (detailed in the Additional file1 ).
Free choline, ethanolamine, creatine, GAA, and MMA were assayed after deproteinization by an LC–MS/MS method adapted from Holm et al. [19 (link)], Imbard et al. [20 (link)], and Cognat et al. [21 (link)]. The analytical system consisted of an Acuity UPLC I Class system (Waters, Milford, USA) coupled with a Xevo-TQD (Waters, Milford, USA) with an Atlantis HILIC analytical column (2.1 × 100 mm, 3 µm) (Waters, Milford, USA).
SAM, SAH, tHcy, Met, betaine, DMG, and sarcosine were measured using new LC–MS/MS developed in our laboratory (detailed in the Additional file