The abundance ratio of intracellular metabolites of M. extorquens AM1 cells between ethylamine culture and succinate culture: (A) GC × GC-TOF-MS, (B) LC-MS/MS. The abbreviation used are α-ketoglu, α-ketoglutaric acid; Pyru, pyruvate; Fum, fumaric acid; Glycer, glyceric acid; MtMal, methylmalonic acid; 3OHB, 3-hydroxybutyric acid; EtMal, ethylmalonic acid; MtSuc, methylsuccinic acid; PEP, phosphoenolpyruvate; Suc-CoA, Succinyl-CoA; OHB-CoA, 3-hydroxybutyryl-CoA; Pro-CoA, Propionyl-CoA; But-CoA, Butyryl-CoA; Glutath (Ox), oxidized glutathione.