Stable isotope phospho-profiling of fibrinogen and fetuin subunits by element mass spectrometry coupled to capillary liquid chromatography

Anal Biochem. 2003 Jun 1;317(1):26-33. doi: 10.1016/s0003-2697(03)00083-6.


We have used one-dimensional polyacrylamide gel electrophoresis, tryptic digestion, and capillary liquid chromatography-mass spectrometry with inductively coupled plasma ionization and phosphorus-31 detection or electrospray ionization for the analysis of protein phosphorylation. We have analyzed human fibrinogen with two well-characterized phosphorylation sites and bovine fetuin with unknown phosphorylation status. Both serine-3 and serine-345 (both in Aalpha) of fibrinogen were clearly recognized. In bovine fetuin, four phosphorylated sites were newly characterized (serine-138, serine-320, serine-323, and serine-324). The novel strategy provides a fast and quantitative overview of the presence of protein phosphorylation sites.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Binding Sites
  • Cattle
  • Electrophoresis, Capillary / methods
  • Electrophoresis, Polyacrylamide Gel
  • Fibrinogen / analysis*
  • Fibrinogen / metabolism
  • Humans
  • Mass Spectrometry / methods
  • Molecular Sequence Data
  • Peptide Fragments / analysis
  • Phosphorus Isotopes
  • Phosphorylation
  • Protein Subunits
  • Serine / metabolism
  • Spectrometry, Mass, Electrospray Ionization
  • alpha-Fetoproteins / analysis*
  • alpha-Fetoproteins / chemistry
  • alpha-Fetoproteins / metabolism


  • Peptide Fragments
  • Phosphorus Isotopes
  • Protein Subunits
  • alpha-Fetoproteins
  • Serine
  • Fibrinogen