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? 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 (Item No. 700940) should be performed in order to truly measure complex III activity.
Size
96 well
Concentration
n/a
Applications
n/a
Other Names
kits assays measures measurements measuring 3 three CoQ coenzymes Q10 cytochromes c oxidoreductases proteins essential oxidatives phosphorylates phosphorylations gatekeeper respirations reactive oxygens species ROSs acceptor electrons e- complexes 1 2 I II one two QH2 ubiquinol ubiquinone carrier bound binds redox reactions reductions oxidations Q-cycles Q cycles Reiske irons sulfurs iron-sulfur Fe-S 2Fe-2S 4Fe-4S 3Fe-4S clusters C1 translocates translocations 4H+ O2- coupled mechanisms inhibits inhibitors inhibitions excess isolates isolations rotenone potassium cyanides KCN