In eukaryotic cells, Isocitrate Dehydrogenase (IDH1, IDH2 and IDH3) is an enzyme that catalyzes the decarboxylation of Isocitrate producing Ketoglutarate and CO2. Mutations in both isoforms of IDH (IDH1 and IDH2) are commonly found in human cancers. The Mutant Isocitrate Dehydrogenase (Mutant IDH) causes a "gain-of-function", which reduces its affinity for isocitrate and favors the conversion of ketoglutarate to D-2-Hydroxyglutarate. D-2-Hydroxyglutarate (D2HG) is present at low level in normal cells and tissues, but is significantly elevated in metabolic diseases and various cancers. D2HG functions as an "oncometabolite" promoting cellular transformation. Recent studies show that increased Mutant IDH activity is associated with various cancers; therefore, detection of Mutant IDH activity is important for diagnosis and developing therapeutic strategies (e.g. Mutant IDH inhibitors). Assay Genie's Mutant IDH assay kit provides a quick and simple assay to monitor the Mutant IDH activity in biological samples. In the assay, Mutant IDH oxidizes NADPH into an NADP+, which decreases the absorbance at 340 nm. The assay is simple, sensitive, and can detect Mutant Isocitrate Dehydrogenase activity lower than 2 mU/ml in a variety of cancer samples.

Figure: (a) NADPH standard curve; (b) Mutant Isocitrate Dehydrogenase activity in MDA-MB-231 Cells Extracts (25 μg), Background control (no Substrate); (c) Mutant Isocitrate Dehydrogenase specific activity was calculated in cell extracts from 3T3 (13 µg), MDA-MB- 231(25 μg) and Jurkat (28 µg). Assays were performed following the kit protocol.