Fig. 4
From: Bridging the gap between non-targeted stable isotope labeling and metabolic flux analysis
MID similarity reflects metabolic similarity and can aid compound identification. Application to an identified and an unidentified compound. a, b The networks show the compounds with the closest MIDs to N-acetylaspartate (NAA) after a [U-13C]glutamine or b [1,2-13C2]glucose labeling. Edge color represents the experimental condition at which the high MID similarity was observed. c Scheme of glycolysis and citric acid cycle showing those compounds with most similar MIDs to NAA after [U-13C]glutamine (blue) or [1,2-13C2]glucose labeling (red). d, e Compounds with the closest MIDs to the unidentified compound RI 2578 after d [U-13C]glutamine or e [1,2-13C2]glucose labeling. f Scheme of metabolic network showing those compounds with most similar MIDs to RI 2578 after [U-13C]glutamine (blue) or [1,2-13C2]glucose labeling (red), supporting its tentative identification as β-citrylglutamate (β-CG). Mal malate, Asp aspartate, Cit citrate, Lac lactate, Glu glutamate, Gln glutamine, Suc succinate, OAA oxaloacetate, 2OG 2-oxoglutarate, Pro proline. See also Additional file 1: Table S4