General description

Isocitrate dehydrogenase (IDH) catalyzes the conversion of isocitrate to α-ketoglutarate. In eukaryotes, there are three isozymes of IDH, the mitochondrial IDH2 and IDH3, and the cytoplasmic/ peroxisomal IDH1. All three IDH family members require the presence of a divalent cation (Mg²⁺ or Mn²⁺) and either the electron-accepting cofactor NADP⁺ (IDH1 and IDH2) or NAD⁺ (IDH3) for their enzymatic activity. IDH1 and IDH2 mutations resulting in neomorphic enzymatic activity are found in certain cancers such as glioblastoma, acute myeloid leukemia, and colon cancer. This neoactivity shows a change in the substrate specificity resulting in the conversion of α-ketoglutarate to 2-hydroxyglutarate. Mutations in IDH family members are also associated with Ollier disease and Maffucci syndrome.

The Isocitrate Dehydrogenase Activity Assay kit provides a simple and direct procedure for measuring NADP⁺-dependent, NAD⁺-dependent, or both NADP⁺ and NAD⁺-dependent IDH activity in a variety of samples. IDH activity is determined using isocitrate as the substrate in an enzyme reaction, which results in a colorimetric (450 nm) product proportional to the enzymatic activity present. One unit of IDH is the amount of enzyme that will generate 1.0 μmole of NADH or NADP per minute at pH 8.0 at 37 °C.