Anti-MAP2K1 (phospho S221) Antibody

This rabbit polyclonal IgG antibody from Antibodies.com selectively recognizes MAP2K1 (also known as MEK1) when phosphorylated at serine 221, a residue within its activation loop that contributes to kinase regulation in the MAPK/ERK cascade. The unconjugated reagent is supplied as a 200 µl volume and has been validated for Western blotting, immunohistochemistry, and immunofluorescence workflows across human, mouse, and rat samples.

MEK1 is a dual-specificity kinase that phosphorylates ERK1/2 downstream of receptor tyrosine kinase, RAS, and BRAF activity, making phospho-site tracking a common readout for pathway engagement. The polyclonal format allows recognition of multiple epitopes surrounding the phosphorylated residue, and the unconjugated IgG isotype enables flexible secondary antibody pairing for fluorescence or chromogenic detection. Recommended handling is storage at -20 °C in working aliquots to limit freeze-thaw cycles, and the reagent is intended for research use only.