Peptide mass mapping constrained with stable isotope-tagged peptides for identification of protein mixtures

Anal Chem. 2001 Oct 15;73(20):4891-902. doi: 10.1021/ac0103322.


Through proteolysis and peptide mass determination using mass spectrometry, a peptide mass map (PMM) can be generated for protein identification. However, insufficient peptide mass accuracy and protein sequence coverage limit the potential of the PMM approach for high-throughput, large-scale analysis of proteins. In our novel approach, nonlabile protons in particular amino acid residues were replaced with deuteriums to mass-tag proteins of the S. cerevisiae proteome in a sequence-specific manner. The resulting mass-tagged proteolytic peptides with characteristic mass-split patterns can be identified in the data search using constraints of both amino acid composition and mass-to-charge ratio. More importantly, the mass-tagged peptides can further act as internal calibrants with high confidence in a PMM to identify the parent proteins at modest mass accuracy and low sequence coverage. As a result, the specificity and accuracy of a PMM was greatly enhanced without the need for peptide sequencing or instrumental improvements to obtain increased mass accuracy. The power of PMM has been extended to the unambiguous identification of multiple proteins in a 1D SDS gel band including the identification of a membrane protein.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Deuterium
  • Electrophoresis, Polyacrylamide Gel
  • Fungal Proteins / analysis*
  • Fungal Proteins / chemistry
  • Isotope Labeling / methods
  • Molecular Sequence Data
  • Peptide Fragments / analysis
  • Peptide Fragments / chemistry
  • Peptide Mapping / methods*
  • Proteome / analysis
  • Proteome / chemistry
  • Saccharomyces cerevisiae / chemistry
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization


  • Fungal Proteins
  • Peptide Fragments
  • Proteome
  • Deuterium