Anti-ATM (phospho S1981) Antibody - Identical to Abcam (ab194865)

The phosphorylation of ATM kinase at serine 1981 is one of the earliest biochemical events after induction of DNA double-strand breaks, making this phospho-epitope a cornerstone readout in DNA damage response studies. Manufactured by Antibodies.com as a rabbit polyclonal IgG and supplied unconjugated, this primary antibody selectively detects ATM only when S1981 is phosphorylated, so researchers can distinguish resting from activated kinase in human cells exposed to genotoxic stress.

The reagent is validated on Western blot and immunohistochemistry: lysates resolved by SDS-PAGE and probed at the expected high molecular weight reveal activation kinetics after insult, while IHC on formalin-fixed paraffin or frozen sections shows nuclear staining in irradiated or drug-treated tissues. Each vial contains 200 µL of liquid antibody; storage at -20 °C is recommended for long-term use, with short-term handling at 4 °C acceptable to preserve phospho-specificity.

Because the antibody is unconjugated, it pairs flexibly with HRP-, biotin-, or fluorophore-conjugated secondary reagents chosen by the user. Common applications include monitoring ATM activation following ionizing radiation, topoisomerase inhibitors, or PARP inhibitor exposure, mapping DNA damage signaling in tumor biopsies, and complementing γH2AX immunostaining to characterize repair pathway engagement in cancer biology, radiobiology, and cell cycle checkpoint research.