When cells undergo apoptosis, they activate endonuclease enzymes that cut genomic DNA between nucleosomes. DNA ladder of 180-200 bp can be detected by electrophoresis after extraction of DNA during apoptosis. TUNEL (TdT mediated dUTP Nick End Labeling) Cell apoptosis Assay Kit (FITC) can be used to detect the nuclear DNA breakage in tissue cells during late apoptotic stage. The principle is that FITC-12-dUTP is inserted into the 3'-hydroxyl (3'-OH) terminal of genomic DNA exposed during DNA break under the action of Terminal Deoxynucleotidyl Transferase (TdT). This can be detected by fluorescence microscopy or flow cytometry. This kit optimizes the labeling reaction by using FITC-12-dUTP and unlabeled dNTP at the optimal ratio for nucleotide incorporation at the 3' -OH terminal, resulting in a longer "labeling tail" at the end of the same broken DNA fragment. The “labeling tail” reduces the steric hindrance of labeled groups on adjacent dNTP, increases the number of fluorescent-groups on each broken fragment, and reduces the aggregation and quenching that may be caused by adjacent fluorescent-groups, thus improving detection sensitivity and reducing non-specific reactions. This kit has a wide range of applications. It can be used to detect apoptosis in frozen or paraffin sections, as well as in culture adherent cells or suspension cells situation. Features The reagents in this kit are provided in liquid form for easy use. The kit can be used for a variety of purposes: flow cytometry, fluorescence microscopy for detection. Under the fluorescence microscope, the color distinction is obvious. Applications This kit can be used for flow cytometry and fluorescence microscopy. This kit can detect the early apoptosis of cells. This kit can distinguish between late apoptotic and necrotic cells. Specifications Application The verified application of the kit was to detect apoptotic cells by flow cytometry or immunofluorescence cytology. Packing form Bottle Components Component Name 40306ES20 (20T) 40306ES50 (50T) 40306ES60 (100T) 40306-A 5×Equilibration Buffer 750 μL 1.25 mL×2 1.25 mL×3 40306-B FITC-12-dUTP Labeling Mix 100 μL 250 μL 250 μL×2 40306-C Recombinant TdT Enzyme 20 μL 50 μL 50 μL×2 40306-D Proteinase K (2 mg/mL) 40 μL 100 μL 100 μL×2 40306-E DNase I (1 U/ μL) 5 μL 12.5 μL 25 μL 40306-F 10 × DNase I Buffer 100 μL 250 μL 500 μL