title: Analysis of low-abundance proteins using the proteomic reactor with pH fractionation.
abstract: We developed a new method consisting of the proteomic reactor coupled with step pH fractionation for the analysis of low-abundance proteins from minute amount of sample. These new reactors were implemented using both SAX and SCX materials. The pH fractions from the SAX reactor provided higher peptide and protein identification than SCX reactor and conventional solution digestion. Interestingly, the physical characteristics (pI, molecular weight, missed cleavage site and grand average hydrophobicity (GRAVY) index, and number of acid and basic amino acid) of the peptides obtained from the SAX and SCX proteomic reactors are drastically different. Furthermore, nearly half of the peptides observed from the pH fractionations from the SAX reactor are of low abundance while only 22% low-abundance proteins are observed with conventional in-solution digestion following 2D LC-MS/MS analysis.
authors.affiliation: Ottawa Institute of Systems Biology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, Canada.
authors.forename: Hu
authors.initials: H
authors.lastname: Zhou
authors.forename: Weimin
authors.initials: W
authors.lastname: Hou
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Lambert
authors.forename: Ruijun
authors.initials: R
authors.lastname: Tian
authors.forename: Daniel
authors.initials: D
authors.lastname: Figeys
mesh_terms: D000595:Amino Acid Sequence; D005591:Chemical Fractionation / Q000379:methods*; D015180:Electrophoresis, Gel, Two-Dimensional / Q000379:methods; D006863:Hydrogen-Ion Concentration; D010455:Peptides / Q000032:analysis* / Q000737:chemistry; D011506:Proteins / Q000032:analysis; D020543:Proteome / Q000032:analysis* / Q000737:chemistry; D040901:Proteomics / Q000379:methods*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods
chemical_list: D010455:Peptides; D011506:Proteins; D020543:Proteome