Artifacts and unassigned masses encountered in peptide mass mapping.
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.
Karty
Jonathan A
JA
Department of Chemistry, Indiana University, Bloomington 47405, USA.
Ireland
Marcia M E
MM
Brun
Yves V
YV
Reilly
James P
JP
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
D010455:Peptides