biovision K127-400 Cell and tissue lysates ? Detection method- Absorbance (400 or 405 nm) ? Species reactivity- Mammalian ? Kit size- Convenient sizes (25, 100, 200, 400 assays) ? Applications- Detect early/middle stages of apoptosis; differentiate apoptosis from necrosis. Caspase-4 Activity Colorimetric Assay Kit: Simple & Convenient Colorimetric Assay to Measure Caspase-4 Activity within 1-2 hrs. Kit Size: 25, 100, 200 and 400 assays. Activation of ICE-family proteases/caspases initiates apoptosis in mammalian cells. The Caspase-4 Colorimetric Assay Kit provides a simple and convenient means for assaying the activity of caspases that recognize the sequence LEVD. The assay is based on spectrophotometric detection of the chromophore p-nitroanilide (pNA) after cleavage from the labeled substrate LEVD-pNA. The pNA light emission can be quantified using a spectrophotometer or a microtiter plate reader at 400- or 405 nm.