Complex II Activity Assay allows for the activity of complex II to be determined without the need to isolate mitochondria or pre-incubate with antibodies. As complex II oxidizes succinate, electrons are passed to an analog of ubiquinone and then on to DCPIP, which, when oxidized, absorbs in the 600 nm range. The absorbance of DCPIP will decrease upon reduction. Complex II activity is measured as a decrease in absorbance at 600 nm over time. To prevent interference from other ETC complexes, rotenone (1 ?M), antimycin A (10 ?M), and potassium cyanide (2 mM) are present as inhibitors (not supplied). For the use of this kit with other types of tissue mitochondria, please see Mitochondrial (Tissue) Isolation Kit.