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Journal of chromatography. B, Analytical technologies in the biomedical and life sciences

Artifacts and unassigned masses encountered in peptide mass mapping.


PMID 12458019

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.