Anti-Histone H2AFX (phospho S2) Antibody

The product targets the phosphorylated serine 2 residue at the N-terminus of Histone H2AFX, a histone H2A variant that constitutes roughly 2–25% of mammalian nucleosomes and is most widely recognized through its C-terminal S139 phospho-mark (γH2AX) as an early indicator of DNA double-strand breaks. The S2 modification sits on the N-terminal tail rather than the canonical C-terminal SQ motif, and phosphorylation at this residue has been characterized separately in chromatin and cell cycle studies, including investigations of nucleosome assembly, replication-coupled chromatin deposition, and genotoxic stress responses.

Antibodies.com supplies this reagent as a rabbit polyclonal IgG, unconjugated, in a 200 µl vial volume. It is validated for Western Blot application and shows reactivity with Human and Rat samples. The polyclonal format supports robust detection of the phospho-S2 epitope across denatured, acid-extracted histone preparations, making the reagent useful for probing modification dynamics in acid-extracted chromatin fractions or whole-cell lysates collected after exposure to DNA-damaging agents such as etoposide, hydroxyurea, or ionizing radiation, as well as after replication stress or checkpoint kinase modulation.

For best results, acid-extract histones from cultured cells or tissue, resolve them on a 15% SDS-PAGE gel, and probe at a working dilution appropriate for immunoblotting. To preserve phospho-specific binding activity, store the vial at -20 °C in working aliquots and limit freeze-thaw cycles; avoid prolonged exposure to ambient temperatures. The unconjugated format allows downstream pairing with HRP- or fluorophore-conjugated secondary antibodies, supporting chemiluminescent or multiplex fluorescence detection workflows. Researchers investigating chromatin signaling, post-translational histone modification crosstalk, or non-canonical H2A.X phosphorylation events can integrate this antibody alongside established γH2AX (S139) reagents to map the spatial and temporal distribution of distinct phospho-marks on the same histone variant.