Programmed cell death, or apoptosis, is a cornerstone of cell biology and medical research, playing a pivotal role in disciplines such as cancer, immunology, and neurodegenerative diseases. Accurate detection of apoptosis is essential for understanding disease mechanisms and developing novel therapies. Annexin V, recognized as the gold-standard protein for early apoptosis detection, binds specifically to phosphatidylserine (PS) exposed on the cell surface, offering researchers a highly sensitive and specific detection method.
Fig. 1 The process of cellular apoptosis.
(Source: National Human Genome Research Institute)
In 2024, a study published in Nature Cancer introduced an Annexin V-based nanoprobe capable of real-time monitoring of apoptosis dynamics in the tumor microenvironment, providing a new tool for precision medicine. Additionally, a 2025 report from the American Society of Clinical Oncology (ASCO) Annual Meeting highlighted Annexin V’s critical role in evaluating the efficacy of CAR-T cell therapies in inducing tumor cell apoptosis, delivering key data to optimize immunotherapies.
Biological Properties of Annexin V
Annexin V is a 35-36 kDa calcium-dependent phospholipid-binding protein belonging to the Annexin family. In healthy cells, PS is primarily located on the inner leaflet of the cell membrane, but during early apoptosis, PS is translocated to the outer surface via a membrane-flipping mechanism, serving as a hallmark of apoptosis. In the presence of calcium ions (Ca²⁺), Annexin V binds PS with an affinity of approximately 10⁻⁹ M, making it an ideal tool for detecting early apoptosis.
Figure 2. Diagram of a normal cell with internal phosphatidylserine; diagram of an apoptotic cell with surface-exposed phosphatidylserine bound by Annexin V.
Applications of Annexin V
When conjugated with fluorescent dyes such as FITC or APC, Annexin V enables analysis via flow cytometry or fluorescence microscopy. Combined with propidium iodide (PI) staining, it distinguishes early apoptosis (Annexin V+/PI-), late apoptosis (Annexin V+/PI+), and necrosis (Annexin V-/PI+), allowing detection of apoptosis before cell membrane integrity is compromised, thus providing high temporal resolution data.
abinScience’s Annexin V recombinant protein is produced using an E. coli expression system, derived from human (Homo sapiens) sequences, ensuring high compatibility with mammalian cells. This protein is versatile for various experimental designs, with typical workflows including:
- Fluorescent Labeling: Conjugate Annexin V with FITC or APC for flow cytometry or fluorescence microscopy detection.
- PI Staining Combination: Use Annexin V with PI to differentiate early apoptosis, late apoptosis, and necrosis.
- Experimental Platforms: Apply in ELISA for quantitative analysis, Western Blot for expression validation, or SDS-PAGE for protein purity assessment.
Product Specifications
The following table outlines the key specifications of abinScience’s Annexin V recombinant protein products:
| Catalog No |
Product Name |
Protein Length |
Applications |
| HY214022 |
Recombinant Human ANXA5 Protein, N-His |
Ala2-Asp320 |
ELISA, Western Blot, SDS-PAGE, Immunogen |
| HY214012 |
Recombinant Human ANXA5 Protein, N-His |
Met1-Asp320 |
ELISA, Western Blot, SDS-PAGE, Immunogen |
About abinScience
abinScience is a global leader in high-quality research reagents, offering recombinant proteins, antibodies, and bulk custom services tailored for life sciences. We collaborate with researchers worldwide to advance studies in apoptosis, cancer, and immunology. Our Annexin V recombinant proteins are designed with scientific precision to accelerate biomedical research and translational applications.
