Research Article

Journal of The American Society for Mass Spectrometry

, Volume 25, Issue 8, pp 1461-1471

First online:

Direct Identification of Tyrosine Sulfation by using Ultraviolet Photodissociation Mass Spectrometry

  • Michelle R. RobinsonAffiliated withDepartment of Chemistry, The University of Texas at Austin
  • , Kevin L. MooreAffiliated withCardiovascular Biology Research Program, Oklahoma Medical Research FoundationDepartment of Cell Biology, University of Oklahoma Health Sciences Center
  • , Jennifer S. BrodbeltAffiliated withDepartment of Chemistry, The University of Texas at Austin Email author 

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access


Sulfation is a common post-translational modification of tyrosine residues in eukaryotes; however, detection using traditional liquid chromatography-mass spectrometry (LC-MS) methods is challenging based on poor ionization efficiency in the positive ion mode and facile neutral loss upon collisional activation. In the present study, 193 nm ultraviolet photodissociation (UVPD) is applied to sulfopeptide anions to generate diagnostic sequence ions, which do not undergo appreciable neutral loss of sulfate even using higher energy photoirradiation parameters. At the same time, neutral loss of SO3 is observed from the precursor and charge-reduced precursor ions, a spectral feature that is useful for differentiating tyrosine sulfation from the nominally isobaric tyrosine phosphorylation. LC-MS detection limits for UVPD analysis in the negative mode were determined to be around 100 fmol for three sulfated peptides, caerulein, cionin, and leu-enkephalin. The LC-UVPD-MS method was applied for analysis of bovine fibrinogen, and its key sulfated peptide was confidently identified.


Ultraviolet photodissociation Sulfation Sulfopeptide Tyrosine