title: Artifacts and unassigned masses encountered in peptide mass mapping.
abstract: In peptide mass mapping of isolated proteins, a significant number of the observed mass spectral peaks are often uninterpreted. These peaks derive from a number of sources: errors in the genome that give rise to incorrect peptide mass predictions, undocumented post-translational modifications, sample handling-induced modifications, contaminants in the sample, non-standard protein cleavage sites, and non-protein components of the sample. In a study of the stalk organelle of Caulobacter crescentus, roughly one-third (782/2215) of all observed masses could not be assigned to the proteins identified in the gel spots (Karty et al., J. Proteome Res., 1 (2002) 325). By interpreting these masses, this work illuminates a number of phenomena that may arise in the course of peptide mass mapping of electrophoretically separated proteins and presents results from a number of related studies.
authors.affiliation: Department of Chemistry, Indiana University, Bloomington 47405, USA.
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Karty
authors.forename: Marcia M E
authors.initials: MM
authors.lastname: Ireland
authors.forename: Yves V
authors.initials: YV
authors.lastname: Brun
authors.forename: James P
authors.initials: JP
authors.lastname: Reilly
mesh_terms: D000595:Amino Acid Sequence; D016477:Artifacts; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010455:Peptides / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D010455:Peptides