Isocitrate dehydrogenase (IDH) enzymes catalyze the oxidative decarboxylation of isocitrate to produce α-ketoglutarate and carbon dioxide. IDH1 and IDH2 isozymes use NADP+ as a cofactor, whereas IDH3 uses NAD+ as cofactor within the citric acid cycle. IDH1 and IDH2 are homodimers and IDH3 is a heterotetramer composed of α, β and γ subunits in a 2:1:1 stoichiometry. Mutations in IDH genes are associated with certain brain tumours [1-2] and acute myeloid leukemia (AML) cells [8]. In general these mutations (for example IDH1^R132H) change the function of the enzymes, reducing production of NADPH and causing production of 2-hydroxyglutarate (2-HG) [3,5], an oncometabolite [4]. Supra-normal levels of 2-HG causes hypermethylation of epigenetic targets [6], leading to malignant transformation [7]. IDH oncogenes have therefore become novel metabolism targets in brain cancers and leukemia.

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