title: Performance of a linear ion trap-Orbitrap hybrid for peptide analysis.
abstract: Proteomic analysis of digested complex protein mixtures has become a useful strategy to identify proteins involved in biological processes. We have evaluated the use of a new mass spectrometer that combines a linear ion trap and an Orbitrap to create a hybrid tandem mass spectrometer. A digested submandibular/sublingual saliva sample was used for the analysis. We find the instrument is capable of mass resolution in excess of 40,000 and mass measurement accuracies of less than 2 ppm for the analysis of complex peptide mixtures. Such high mass accuracy allowed the elimination of virtually any false positive peptide identifications, suggesting that peptides that do not match the specificity of the protease used in the digestion of the sample should not automatically be considered as false positives. Tandem mass spectra from the linear ion trap and from the Orbitrap have very similar ion abundance ratios. We conclude this instrument will be well suited for shotgun proteomic types of analyses.
authors.affiliation: Department of Cell Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA. jyates@scripps.edu
authors.forename: John R
authors.initials: JR
authors.lastname: Yates
authors.forename: Daniel
authors.initials: D
authors.lastname: Cociorva
authors.forename: Lujian
authors.initials: L
authors.lastname: Liao
authors.forename: Vlad
authors.initials: V
authors.lastname: Zabrouskov
mesh_terms: D006801:Humans; D008666:Metalloendopeptidases / Q000378:metabolism; D040901:Proteomics / Q000295:instrumentation / Q000379:methods*; D012463:Saliva / Q000737:chemistry*; D012471:Salivary Proteins and Peptides / Q000032:analysis* / Q000378:metabolism; D053719:Tandem Mass Spectrometry / Q000295:instrumentation / Q000379:methods*
chemical_list: D012471:Salivary Proteins and Peptides; D008666:Metalloendopeptidases; C039830:peptidyl-Lys metalloendopeptidase