Identification and characterization of phosphorylated proteins in the human pituitary

Proteomics. 2004 Mar;4(3):587-98. doi: 10.1002/pmic.200300584.


Post-translational modifications of proteins from the human pituitary gland play an important role in the regulation of different body functions. We report on the application of a liquid chromatography-tandem mass spectrometry (MS/MS) based approach to detect and characterize phosphorylated proteins in a whole human pituitary digest. By combining an immobilized metal affinity column-based enrichment method with MS/MS conditions that favor the neutral loss of phosphoric acid from a phosphorylated precursor ion, we identified several previously undescribed phosphorylated peptides. The identified peptides were matched to the sequences of six pituitary proteins: the human growth hormone, chromogranin A, secretogranin I, 60S ribosomal protein P1 and/or P2, DnaJ homolog subfamily C member 5, and galanin. The phosphorylation sites of these important regulatory proteins were determined by MS/MS and MS(3) analysis.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Chromogranin A
  • Chromogranins / chemistry
  • Databases as Topic
  • Galanin / chemistry
  • Human Growth Hormone / chemistry
  • Humans
  • Ions
  • Mass Spectrometry / methods*
  • Molecular Sequence Data
  • Peptides / chemistry
  • Phosphopeptides / chemistry
  • Phosphorylation
  • Pituitary Gland / metabolism*
  • Protein Processing, Post-Translational
  • Time Factors
  • Trypsin / chemistry


  • Chromogranin A
  • Chromogranins
  • Ions
  • Peptides
  • Phosphopeptides
  • Human Growth Hormone
  • Galanin
  • Trypsin