A highly facile and specific assay for cancer-causing isocitrate dehydrogenase mutant using 13C4-labeled...

Isocitrate dehydrogenase mutations with neomorphic activity of converting α-ketoglutarate to 2-hydroxyglutarate have been found in many types of cancers. We report an NMR-based assay specific for the mutant using (13)C4-labeled α-ketoglutarate. It can be done in a complex mixture without extraction, give time-dependent absolute quantitation, and be applied to enzyme inhibition studies. Its merits over conventional assays should facilitate inhibitor developments for a new class of target-oriented anticancer agents.