Anti-Btk (phospho Y223) Antibody

Affinity-purified rabbit polyclonal IgG reagent from Antibodies.com, raised against a phospho-specific peptide corresponding to residues surrounding tyrosine 223 of human Bruton's tyrosine kinase (Btk), the dominant autophosphorylation site used to read out kinase engagement downstream of the B-cell receptor. The unconjugated antiserum is supplied as 100 µl in a vial, formulated in phosphate buffered saline at pH 7.30 with 0.02% sodium azide and 50% glycerol as a cryoprotectant. Recommended dilutions are 1:500 to 1:2000 for Western blot and 1:20 to 1:100 for immunofluorescence on human, mouse, and rat samples. Researchers working on B-cell receptor signalling, X-linked agammaglobulinemia models, B-cell lymphoma biology, and the cellular response to covalent Btk inhibitors such as ibrutinib pair this phospho-Y223 reagent with a total-Btk loading control so that kinase activation can be normalized to total Btk expression. Standard PVDF western workflows, phospho-tyrosine-compatible blocking buffers, and standard IF fixation protocols are compatible with the reagent. Aliquot upon first use, refrigerate the vial, and avoid repeated freeze-thaw cycles to preserve recognition of the phospho-epitope.