Annexin V-Fluor 647/PI Apoptosis Detection Kit

Description

The Annexin V–Alexa Fluor 647/PI Apoptosis Detection Kit is designed for the detection of early apoptosis using Alexa Fluor 647–labeled Annexin V as a fluorescent probe. Detection can be performed by flow cytometry or other fluorescence-based analytical instruments. In viable cells, phosphatidylserine (PS) is confined to the inner leaflet of the plasma membrane. During early apoptosis, PS is translocated to the outer leaflet and becomes exposed to the extracellular environment. Annexin V is a 35–36 kDa Ca²⁺-dependent phospholipid-binding protein that binds PS with high affinity, enabling selective labeling of early apoptotic cells.

PI is a nucleic acid dye that cannot penetrate intact cell membranes but readily enters cells with compromised membrane integrity, staining the nucleus red. When used together, live cells remain Annexin V⁻/PI⁻, early apoptotic cells are Annexin V⁺/PI⁻, and late apoptotic or necrotic cells display double-positive staining (Annexin V⁺/PI⁺). This dual-staining approach enables accurate discrimination of different stages of cell death.