Quantitative Analysis of in Vivo Methionine Oxidation of the Human Proteome

J Proteome Res. 2020 Feb 7;19(2):624-633. doi: 10.1021/acs.jproteome.9b00505. Epub 2020 Jan 7.


The oxidation of methionine is an important post-translational modification of proteins with numerous roles in physiology and pathology. However, the quantitative analysis of methionine oxidation on a proteome-wide scale has been hampered by technical limitations. Methionine is readily oxidized in vitro during sample preparation and analysis. In addition, there is a lack of enrichment protocols for peptides that contain an oxidized methionine residue, making the accurate quantification of methionine oxidation difficult to achieve on a global scale. Herein, we report a methodology to circumvent these issues by isotopically labeling unoxidized methionines with 18O-labeled hydrogen peroxide and quantifying the relative ratios of 18O- and 16O-oxidized methionines. We validate our methodology using artificially oxidized proteomes made to mimic varying degrees of methionine oxidation. Using this method, we identify and quantify a number of novel sites of in vivo methionine oxidation in an unstressed human cell line.

Keywords: hydrogen peroxide; methionine oxidation; oxidative protein damage; quantitative proteomics; redox chemistry.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Humans
  • Methionine* / metabolism
  • Oxidation-Reduction
  • Peptides
  • Protein Processing, Post-Translational
  • Proteome* / metabolism


  • Peptides
  • Proteome
  • Methionine