Description

BioLegend’s FITC Annexin V Apoptosis Detection Kit with PI has been specifically designed for
the identification of apoptotic and necrotic cells.
Annexin V (or Annexin A5) is a member of the annexin family of intracellular proteins that binds
to phosphatidylserine (PS) in a calcium-dependent manner. PS is normally only found on the
intracellular leaflet of the plasma membrane in healthy cells, but during early apoptosis,
membrane asymmetry is lost and PS translocates to the external leaflet. Fluorochrome-labeled
Annexin V can then be used to specifically target and identify apoptotic cells. Annexin V
Binding Buffer is recommended for use with Annexin V staining. Annexin V binding alone
cannot differentiate between apoptotic and necrotic cells. To help distinguish between the
necrotic and apoptotic cells we recommend use of our Propidium Iodide Solution (PI). Early
apoptotic cells will exclude PI, while late stage apoptotic cells and necrotic cells will stain
positively, due to the passage of these dyes into the nucleus where they bind to DNA.
Propidium iodide is a fluorescent dye that binds to DNA. When excited by 488 nm laser light, it
can be detected with in the PE/Texas Red® channel with a bandpass filter 610/10. It is
commonly used in evaluation of cell viability or DNA content in cell cycle analysis by flow
cytometry