BD Cy™5 Annexin V

Apoptosis is a normal physiologic process which occurs during embryonic development as well as in maintenence of tissue homeostasis. The apoptotic program is characterized by certain morphologic features, including loss of plasma membrane asymmetry and attachment, condensation of cytoplasm and nucleus, and internucleosomal cleavage of DNA. Loss of plasma membrane is one feature. In apoptotic cells, membrane phospholipid phosphatidylserine (PS) is translocated from inner to outer leaflet of plasma membrane, thereby exposing PS to external cellular environment. Annexin V is a 35-36 kDa Ca2+ dependent phospholipid-binding protein that has a high affinity for PS, and binds to cells with exposed PS. Annexin V may be conjugated to fluorochromes including Cy5. This format retains its high affinity for PS and thus serves as a sensitive probe for flow cytometric analysis of cells that are undergoing apoptosis. Since externalization of PS occurs in earlier stages of apoptosis, Cy5 Annexin V staining can identify apoptosis at an earlier stage than assays based on nuclear changes such as DNA fragmentation. Cy5 Annexin V staining precedes loss of membrane integrity which accompanies latest stages of cell death resulting from either apoptotic or necrotic processes. Therefore, staining with Cy5 Annexin V is typically used in conjunction with a vital dye such as propidium iodide (PI) or 7-Amino-Actinomycin (7-AAD) to allow investigator to identify early apoptotic cells (7-AAD negative, Cy5 Annexin V positive)

• Format: Cy5
• Cy5 Annexin V staining precedes the loss of membrane integrity
• Used in conjunction with a vital dye such as propidium iodide (PI) or 7-Amino-Actinomycin (7-AAD)
• Emission wavelength: 670nm
• Excitation wavelength: 625 - 650nm

Flow cytometry