The MMP Orange Reagent Kit assesses changes in MMP, an indicator of mitochondrial health. The cell-permeable MMP Orange Reagent accumulates in active mitochondria in proportion to the MMP generated by the electrochemical gradient across the mitochondrial membrane. A drop in MMP denotes a disruption in mitochondrial function and/or integrity and can also be used as an early indicator of apoptosis. This assay kit utilizes two control compounds: FCCP, an uncoupling agent that transports H+ ions across the mitochondrial membrane and results in depolarization (indicated by a decrease in fluorescence), and Oligomycin A, an inhibitor of ATP synthase which results in hyperpolarization (indicated by an increase in fluorescence).