Anti-Histone H2A.X (phospho-S139) Antibody

The phospho-S139 form of histone H2A.X, commonly referred to as gamma-H2AX, is generated within minutes at chromatin flanking DNA double-strand breaks and acts as one of the earliest markers of the cellular DNA damage response. This rabbit polyclonal reagent from Antibodies.com recognises the phosphorylated serine 139 epitope on H2A.X, allowing researchers to monitor damage induction, repair kinetics, and genotoxic stress in cultured cells and in tissue sections.

The antibody is supplied at 1 mg/ml in phosphate buffered saline containing 0.05% sodium azide at approximately pH 7.2, packaged as a 100 ul vial of ready-to-use liquid. It has been validated for western blot and immunohistochemistry on samples derived from human, mouse, and rat, and is supplied unconjugated so that it can be paired with a secondary reporter of the researcher's choice, including HRP, biotin, or fluorophore-conjugated secondaries. Typical applications include tracking ATM- and ATR-dependent signalling after ionising radiation, chemotherapeutic exposure, or CRISPR/Cas9 editing, as well as visualising nuclear foci alongside markers such as 53BP1 in immunofluorescence workflows.

For handling, aliquot the antibody upon first use to limit freeze-thaw cycles and store the vial at -20 degrees C; the sodium azide already in the formulation acts as a preservative. A brief centrifugation step is recommended before dilution if the reagent has been held at sub-zero temperatures, as small amounts of aggregated protein may otherwise accumulate during frozen storage.