Comparative profiling of human saliva by intact protein LC/ESI-TOF mass spectrometry

Biochim Biophys Acta. 2007 Jul;1774(7):897-906. doi: 10.1016/j.bbapap.2007.04.017. Epub 2007 May 10.


Human saliva is finding increasing interest for proteomic and biomarker-discovery studies, due to the ease of collection and potential for simpler processing workflows compared to serum or plasma. However, it is known that salivary protein composition can vary with physiological and environmental factors. In this work, we have examined intra- and inter-person variability of saliva protein composition using an LC/MS methodology to profile low molecular weight human salivary proteins. Whole saliva was analyzed from four individuals over three consecutive days. Additional samples were used to determine baseline analytical and sample processing variation and to identify phosphoproteins. Individuals were observed to have a similar salivary protein pattern over multiple days, although the expression levels of particular proteins were variable. Significant differences in protein profiles were observed between subjects, allowing for delineation of individuals based on their protein profile. Comparison with alkaline phosphatase treated saliva revealed that several identified proteins were singly, doubly, or triply phosphorylated.

MeSH terms

  • Adult
  • Alkaline Phosphatase / metabolism
  • Chromatography, Liquid / methods*
  • Cluster Analysis
  • Gene Expression Profiling
  • Humans
  • Ions
  • Mass Spectrometry
  • Phosphoproteins / chemistry
  • Phosphorylation
  • Protein Array Analysis
  • Saliva / metabolism*
  • Salivary Proteins and Peptides / chemistry*
  • Salivary Proteins and Peptides / metabolism
  • Spectrometry, Mass, Electrospray Ionization / methods*
  • Time Factors


  • Ions
  • Phosphoproteins
  • Salivary Proteins and Peptides
  • Alkaline Phosphatase