Fig. 2.

Schematic summary of intracellular glutamine metabolism. Glutamine is involved in the synthesis of four main macromolecules in the cytosol: proteins, nucleotides, lipids and fatty acids. In mitochondria, alpha-ketoglutarate derived from glutamine can be further metabolised either by oxidation involving the TCA cycle, termed as the glutaminolysis pathway (indicated by blue arrows), leading to lactate production, or by the reductive carboxylation pathway (indicated by red arrows), leading to lipid synthesis. Gln glutamine, Glc glucose, Glu glutamate, α-KG α-ketoglutarate, Mal malate, OAA oxaloacetate, Cit citrate, GSH glutathione, aa acid amine, Gly glycine, Ser serine, Cys cysteine (Color figure online)