MitoCheck(R) Complex II/III Activity Assay Kit

Complex III (CoQ cytochrome c oxidoreductase) is an essential protein for mitochondrial oxidative phosphorylation. Complex III functions as both a gatekeeper for mitochondrial respiration and as a major source of reactive oxygen species III. It accepts electrons from complexes I and II in the form of QH2, the reduced form of the electron carrier ubiquinone. Once bound to complex III, QH2 undergoes a series of redox reactions, known as the Q-cycle. During the Q-cycle, electrons are passed from QH2 onto cytochrome c via the Rieske iron-sulfur protein and cytochrome c1 resulting in the translocation of 4H+ and the generation of 02-. Cayman's MitoCheck(R) Complex II/III Activity Assay measures the reduction of excess cytochrome c (550 nm absorbance) as catalyzed by complex III. This assay is coupled to succinate co-enzyme Q oxidoreductase (complex II) for the generation of QH2. Due to the dependence on complex II activity, a counter-screen for complex II activity (Cay-700940) should be performed in order to truly measure complex III activity. For the use of this kit with other types of tissue mitochondria, please see Cayman's MitoCheck(R) Mitochondrial (Tissue) Isolation Kit (Cay-701010).Origin: Animal/Bovine, Animal/Horse.