ac202899p_si_006.xls (1.27 MB)

Capillary Zone Electrophoresis-Electrospray Ionization-Tandem Mass Spectrometry as an Alternative Proteomics Platform to Ultraperformance Liquid Chromatography-Electrospray Ionization-Tandem Mass Spectrometry for Samples of Intermediate Complexity

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posted on 07.02.2012, 00:00 by Yihan Li, Matthew M. Champion, Liangliang Sun, Patricia A. DiGiuseppe Champion, Roza Wojcik, Norman J. Dovichi
We demonstrate the use of capillary zone electrophoresis with an electrokinetically pumped sheath-flow electrospray interface for the analysis of a tryptic digest of a sample of intermediate protein complexity, the secreted protein fraction of Mycobacterium marinum. For electrophoretic analysis, 11 fractions were generated from the sample using reverse-phase liquid chromatography; each fraction was analyzed by CZE-ESI-MS/MS, and 334 peptides corresponding to 140 proteins were identified in 165 min of mass spectrometer time at 95% confidence (FDR < 0.15%). In comparison, 388 peptides corresponding to 134 proteins were identified in 180 min of mass spectrometer time by triplicate UPLC-ESI-MS/MS analyses, each using 250 ng of the unfractionated peptide mixture, at 95% confidence (FDR < 0.15%). Overall, 62% of peptides identified in CZE-ESI-MS/MS and 67% in UPLC-ESI-MS/MS were unique. CZE-ESI-MS/MS favored basic and hydrophilic peptides with low molecular masses. Combining the two data sets increased the number of unique peptides by 53%. Our approach identified more than twice as many proteins as the previous record for capillary electrophoresis proteome analysis. CE-ESI-MS/MS is a useful tool for the analysis of proteome samples of intermediate complexity.