As an organelle, mitochondria is the "power factory" in cells and the main site of aerobic respiration of cells. Its function is to convert energy through oxidative phosphorylation to provide energy for cellular activities. The oxidation process is carried out by four respiratory chain membrane protein complexes (complexes I, II, III and IV) on the inner mitochondrial membrane. mitochondrial complex III, also known as cytochrome c reductase complex, its main function is to oxidize the reduced coenzyme Q10 formed by mitochondrial complexes I and II to oxidative coenzyme Q10. In this process, the OD value increased at 550 nm. Therefore, the activity of mitochondrial complex III can be quantified by measure the change OD value at 550 nm.
