NucView® Caspase-3 Substrates consist of a fluorogenic DNA dye and a DEVD substrate moiety specific for caspase-3. The substrate, which is initially not fluorescent and nonfunctional as a DNA dye, crosses the cell membrane to enter the cytoplasm, where it is cleaved by caspase-3 to form a high- affinity DNA dye. The released dye can bind DNA, resulting in bright nuclearfluorescence (Figure 1), allowing caspase-3 activity to be monitored in individual intact cells in real time. NucView® substrates also can be used in a rapid and convenient homogenous end-point assay.