WB (peptide competition) analysis of HEK293 cells overexpressing c-Raf unstimulated (Lane 1) or stimulated with active Src (Lane 2-5) using GTX24769 Raf1 (phospho Tyr340/Tyr341) antibody prior incubated with non-phosphopeptide corresponding to the phosphopeptide immunogen (Lane 3), a generic phosphotyrosine-containing peptide (Lane 4), or the phosphopeptide immunogen (Lane 5). The data show that only the immunogen phosphopeptide blocks the signal, demonstrating the specificity of the antibody.