The DeadEnd™ Colorimetric TUNEL system is a modified TUNEL (TdT-mediated dUTP Nick-End Labeling) assay used to detect the apoptotic cells in situ at the single-cell level.

• Simple and accurate
• Measures nuclear DNA fragmentation
• Proven applications include Vibratome® sections of neuronal tissue, Jurkat cells, HL-60 cells

The fragmented DNA of apoptotic cells is end-labeled using a modified TUNEL assay. Biotinylated nucleotide is incorporated at the 3´-OH DNA ends using Terminal Deoxynucleotidyl Transferase (TdT). Horseradish-peroxidase-labeled streptavidin (Streptavidin HRP) is then bound to these biotinylated nucleotides, which are detected using the peroxidase substrate, hydrogen peroxide, and the stable chromogen, diaminobenzidine (DAB). Using this procedure, apoptotic nuclei are stained dark brown.