Plasma Fractionation and Mixture Improves Coverage in Proteomic Analysis

Expanding plasma proteome coverage increases the success in proteomic discovery of blood biomarkers. Here we report that the sequential precipitation of plasma by increasing concentrations of acetonitrile (AcN) can fractionate proteins. Combining some of these fractions with other fractions from polyethylene glycol (PEG) precipitation and albumin depletion to have the mixed sample that included these partitioned fractions: 10% whole plasma, 20% 20%-AcN-pellet, 10% 40%-AcN-pellet, 20% 50%-AcN-supernatant, 20% 10%-PEG-precipitation-albumin-depletion, and 20% 20%-PEG-precipitation-albumin-depletion, has yielded identification of 5441 proteins, remarkably larger than the 2040 proteins detected in the whole plasma directly. This study provides nearly the largest plasma proteomics data sets and recommends this fractionation and mixture strategy as an efficient approach for expanded plasma proteomics coverage.