Fig. 1.

The ion currents of phosphopeptides as a function of the incubation time with Pho80/Pho85 before normalization. (A) SNSpSPYLNKR ([MH₂]²⁺ at m/z 623.28). (B) TSSSAEGVVVASEpSPVIAPHGSTHAR ([MH₃]³⁺ at m/z 871.75). Error bar indicates one standard deviation. (C) Plot of the relative deviations from the mean signal intensities of proteolytic peptides derived from Pho4 to determine good peptides (solid lines) and outliers (broken lines). The normalized signal intensities for the phosphopeptides SNSpSsPYLNKR ([MH₂]²⁺ at m/z 623.28) (D) and TSSSAEGVVVASEpSPVIAPHGSTHAR ([MH₃]³⁺ at m/z 871.75) (E) are shown. The curves represent the modeled phosphorylation kinetics based on previous ³²P-labeling and phosphopeptide-mapping data (19).