Description
This kit enables enable detection of apoptosis in intact cell populations based on the measurement of caspase-3/7 activity using either a fluorescence microplate reader or a fluorescence imaging system. Caspase-3 and caspase-7 are proteases that are activated during the execution phase of apoptosis. NucView 488 Caspase-3 substrate (formulated in DMSO or phosphate-buffered saline (PBS), for EarlyTox Caspase-3/7-D NucView 488 Assay Kit and EarlyTox Caspase-3/7 NucView 488 Assay Kit, respectively) is used to detect caspase-3/7 activity within intact cells without interfering with caspase activity. The substrate consists of a fluorogenic DNA dye that is coupled to the caspase-3/7 DEVD recognition sequence. Initially non-fluorescent, the substrate permeates the plasma membrane and enters the cytoplasm. In apoptotic cells, caspase-3/7 cleaves the substrate, releasing a high-affinity DNA dye that migrates to the cell nucleus and stains DNA with bright green fluorescence, with excitation at 500 nm and emission at 530 nm. NucView 488 staining is formaldehyde-fixable and compatible with subsequent immunostaining. The assay kit includes an optional masking reagent to reduce background fluorescence when necessary. The PBS formulation is recommended for cells that are sensitive to DMSO.