Annexin V is a Ca2 -dependent phospholipid-binding protein that specifically binds phosphatidylserine (PS) Under normal conditions PS is located on the inner side of the plasma membrane lipid bilayer however during early apoptosis PS translocates from the inner leaflet to the outer surface of the cell membrane becoming exposed to the extracellular environment Annexin V has a high affinity for PS Fluorescent (APC)-labeled Annexin V serves as a fluorescent probe enabling detection of apoptotic cells using flow cytometry or fluorescence microscopy The staining procedure takes only 15-30 minutes to complete Use of this reagent requires additional purchase of 10X Binding Buffer (Catalog no K2284) To further characterize different apoptosis stages Annexin V can be combined with nuclear dyes such as 7-AAD DAPI PI or SYTOX Green These nuclear dyes specifically bind double-stranded DNA generating fluorescence Normally they cannot penetrate intac