Electron-transfer dissociation (ETD) is a method of fragmenting ions in a mass spectrometer. Similar to electron-capture dissociation, ETD induces fragmentation of cations (e.g. peptides or proteins) by transferring electrons to them. It was invented by Donald F. Hunt, Joshua Coon, John E. P. Syka and Jarrod Marto at the University of Virginia.
 ETD fragmentation
where A is the anion. ETD cleaves randomly along the peptide backbone (so called c and z ions) while side chains and modifications such as phosphorylation are left intact. The technique only works well for higher charge state ions (z>2), however relative to collision-induced dissociation (CID), ETD is advantageous for the fragmentation of longer peptides or even entire proteins. This makes the technique important for top-down proteomics.
 See also
- Syka JE, Coon JJ, Schroeder MJ, Shabanowitz J, Hunt DF (2004). "Peptide and protein sequence analysis by electron transfer dissociation mass spectrometry". Proc. Natl. Acad. Sci. U.S.A. 101 (26): 9528–33. Bibcode:2004PNAS..101.9528S. doi:10.1073/pnas.0402700101. PMC 470779. PMID 15210983.
- Mikesh LM, Ueberheide B, Chi A, Coon JJ, Syka JE, Shabanowitz J, Hunt DF (2006). "The utility of ETD mass spectrometry in proteomic analysis". Biochim. Biophys. Acta 1764 (12): 1811–22. doi:10.1016/j.bbapap.2006.10.003. PMC 1853258. PMID 17118725.
- US patent 7534622, Donald F. Hunt, Joshua J. Coon, John E.P. Syka, Jarrod A. Marto, "Electron transfer dissociation for biopolymer sequence mass spectrometric analysis", issued 2009-05-19
- McLuckey SA, Stephenson JL (1998). "Ion/ion chemistry of high-mass multiply charged ions". Mass spectrometry reviews 17 (6): 369–407. doi:10.1002/(SICI)1098-2787(1998)17:6<369::AID-MAS1>3.0.CO;2-J. PMID 10360331.
- Chi A, Huttenhower C, Geer LY, Coon JJ, Syka JE, Bai DL et al. (2007). "Analysis of phosphorylation sites on proteins from Saccharomyces cerevisiae by electron transfer dissociation (ETD) mass spectrometry.". Proc Natl Acad Sci U S A 104 (7): 2193–8. Bibcode:2007PNAS..104.2193C. doi:10.1073/pnas.0607084104. PMC 1892997. PMID 17287358.