Figure 3.

Schematic representation of a chemical fractionation strategy applied to the plasma proteome characterization. High abundance proteins were firstly removed using immunoaffinity subtraction. The resulting less-abundant proteins were split and subjected to solid-phase cysteinyl peptide and N-glycoprotein captures, independently. Noncysteinyl peptides and non-glycopeptides generated at the same time were also collected. All 4 different peptide populations were then fractionated by SCX chromatography and each fraction was analyzed by capillary LC-MS/MS.