Fluorescent conjugates of Annexin V

Fluorescent conjugates of Annexin V can be used to label apoptotic cells. The human anticoagulant Annexin V is a 35-36 kDa, Ca2+-dependent phospholipid-binding protein with high affinity for phosphatidylserine (PS). In viable cells, PS is located on the inner leaflet of the cytoplasmic membrane. In apoptotic cells, PS translocates from the inner to the outer leaflet of the plasma membrane, where it can bind to fluorescent Annexin V for detection by microscopy or flow cytometry. Annexin V conjugates commonly are provided in solution with azide as a preservative for end-point staining assays.