Apoptosis and necrosis are two major processes by which cells die. Apoptosis is an active, genetically regulated disassembly of the cell from within. During apoptosis, phosphatidylserine (PS) is translocated from the inner to the outer surface of the cell for phagocytic cell recognition. The human anticoagulant Annexin V is a 35 kDa, Ca2 -dependent phospholipid-binding protein with a high affinity for PS. Annexin V labeled with fluorescein (FITC) (λEx/λEm = 492/514 nm) can identify apoptotic cells in green by binding to PS exposed on the outer leaflet. Necrosis normally results from a severe cellular insult, resulting in loss of plasma membrane integrity. Ethidium homodimer III (EthD-III) is a highly positively charged nucleic acid probe, which is impermeant to live cells or apoptotic cells, but stains necrotic cells with red fluorescence (λEx/λEm (with DNA) = 528/617 nm). EthD-III is a superior alternative to propidium iodide (PI) or ethidium homodimer I because of its significantly higher affinity for DNA and higher fluorescence quantum yield. The Apoptosis & Necrosis Quantification Kit provides a convenient assay for quantifying apoptotic (green) and necrotic (red) cells within the same cell population by flow cytometry or fluorescence microscopy.
Ethidium homodimer III
5X binding buffer
Simple: Simultaneous detection of both apoptotic and necrotic cells in a single assay
Fast: A single 15-30 min staining step
Sensitive: EthD-III is a superior alternative to both PI and EthD-I for staining necrotic cells.
Also see the Apoptosis and Necrosis Quantitation Kit Plus (catalog no. 30065) and Apoptotic, Necrotic, and Healthy Cells Quantitation Kit Plus (catalog no. 30066), which feature Annexin V conjugated to Biotium’s superior green fluorescent dye CF488A, which is brighter and more photostable than FITC.