Phosphoproteomic Profiling of In Vivo Signaling in Liver by the Mammalian Target of Rapamycin Complex 1 (mTORC1)
Figure 2
Phosphopeptide enrichment by SCX Chromatography.
Upper Panel: Peptide SCX chromatography separation at pH 2.65 of a liver homogenate fraction. Digested peptides (10 mg) were applied to a Resource S SCX column and eluted using a 5 mM to 1.5 M ammonium formate gradient. The peptide content of each fraction was estimated by measuring the absorbance at 280 nm. Two fraction pools containing the highest peptide amounts (Peaks 1 and 2) were recovered from each column run. The figure shows a representative result using the 300 mM NaCl SAX fraction of the control 1 liver sample. Lower Panel: The number of phosphopeptides identified from peak 1 (filled bars) versus peak 2 (unfilled bars) is shown as a function of whether those phosphopeptides contained one, two or three phosphorylation sites.