Additional file 3: of Csk-homologous kinase (Chk) is an efficient inhibitor of Src-family kinases but a poor catalyst of phosphorylation of their C-terminal regulatory tyrosine

Figure S7. Extracted ion chromatogram (XIC) for the C terminal peptide containing the Tyr-527 phosphorylation site of Src in the presence and absence of Csk. A-D Src (K295M) alone (A) Src (K295M) with Csk (B), Src alone (C) and Src with Csk (D) were incubated with ATP and assay buffer. Peptides are identified by Mascot in accordance of retention time. Retention time and mass error (ppm) are shown. E. Isotope dot product (idotp) comparing the observed and theoretical distribution of the precursor isotope with 1.0 being an optimal match. (TIFF 688 kb)