Human Phospho-NBS1 (S343) PharmaGenie ELISA Kit (SBRS1909)

The phospho-NBS1 (S343) ELISA from Assay Genie quantifies an ATM-dependent modification on the NBN protein, which assembles into the MRN complex (MRE11-RAD50-NBS1) at DNA double-strand breaks. Phosphorylation at serine 343 appears within minutes of ionizing radiation or other genotoxic stress and serves as a quantitative biomarker of ATM kinase activation and downstream DNA damage signaling. The colorimetric assay is run on a microplate pre-coated with capture antibodies specific for the phosphorylated epitope, with sensitivity down to 0.1 ng/mL of phospho-NBS1 (S343) and a working assay range of 0.156–10 ng/mL. The protocol uses 100 µL of sample per well and is validated for human cell lysates and tissue lysates, enabling kinetic monitoring of DNA damage signaling. Store at 4°C, refrigerate unopened plates, and aliquot reagents to minimize freeze-thaw cycles. The kit supports research use only workflows in radiation biology, genotoxicity screening, and DNA repair pathway analysis.