Succinate Dehydrogenase (SDH) (EC 1.3.5.1) or succinate-coenzyme Q reductase (SQR) or respiratory complex II is an enzyme complex, which is bound to the inner mitochondrial membrane. SDH participates in both the citric acid cycle and electron transport chain. In mammals and many bacteria, SDH consists of 2 hydrophilic subunits, SDHA (flavoprotein) and SDHB (iron-sulfur protein) and 2 hydrophobic membrane anchor subunits: SDHC and SDHD. SDH oxidizes succinate to fumarate and transfers the electrons to ubiquinone. SDH deficiency in humans leads to a variety of phenotypes including Leigh syndrome, a neurometabolic disorder, tumor formation, and myopathy. Recent studies show that SDH can prevent the generation of ROS (reactive oxygen species); therefore, measurement of succinate dehydrogenase activity has wide applications. Assay Genie's Succinate Dehydrogenase Activity Assay kit is rapid, simple and high-throughput adaptable. In this assay, Succinate dehydrogenase converts succinate to fumarate, and transfers the electron to an artificial electron acceptor (Probe), which changes the color from blue to a colorless product (depending upon the sample enzymatic activity). This assay kit can detect less than 0.1mU Succinate Dehydrogenase Activity in a variety of samples.

Figure: (a) DCIP Standard Curve (b) Measurement of Succinate Dehydrogenase Activity in Positive Control (22 µg) (c) Mitochondria isolated from mouse heart (24 µg) and liver (70 µl).