Ketoglutarate Dehydrogenase (KGDH) (EC 1.2.4.2) is a key enzyme in the citric acid cycle. It forms an enzyme complex with dihydrolipoamide succinyl transferase (E2) and dihydrolipoamide dehydrogenase (E3). KGDH converts ketoglutarate into succinyl-CoA in the presence of NAD and CoA. It is highly regulated by intracellular ATP/ADP and NADH/NAD ratios and calcium. In humans, decreased KGDH activity can lead to neurodegenerative diseases such as Alzheimer's disease. Recent studies show that KGDH is a target of oxidative stress; reactive oxygen species (ROS) inhibit KGDH activity which diminishes its critical function and can cause a bioenergetic deficit. Assay Genie's KGDH assay kit provides a quick and easy way for monitoring KGDH activity in various samples. In the assay, KGDH converts ketoglutarate into an intermediate which reduces the probe to a colored product with strong absorbance at 450 nm. The assay is simple, sensitive and can detect ketoglutarate dehydrogenase activity lower than 0.1 mU in a variety of samples.

Figure: (a) NADH standard curve; (b) α-Ketoglutarate Dehydrogenase activity in rat heart (75 μg) and liver lysates (100 μg); (c) α-Ketoglutarate Dehydrogenase specific activity was calculated in rat heart lysate (75 μg), yeast mitochondria prepared from S.Cerevisiae (10 µg) and in rat liver lysate (100 μg). Assays were performed following the kit protocol.