Ion activation in electron capture dissociation to distinguish between N-terminal and C-terminal product ions

Yury O. Tsybin, Huan He, Mark Emmett, Christopher L. Hendrickson, Alan G. Marshall

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We present a method to distinguish N-terminal from C-terminal product ions in electron capture dissociation (ECD) MS/MS due to the change in relative abundances of even-electron (prime) and odd-electron (radical) product ions produced in consecutive ECD and activated ion-ECD mass spectra. The method is based on the rate and direction of hydrogen atom transfer between N-terminal and C-terminal ECD products and its dependence on ion internal energy. We demonstrate that increasing ion internal energy by vibrational activation prior to ECD results in decreased ratio of radical/prime N-terminal product ions (c./c′ ratio), but increased ratio of radical/prime C-terminal product ions (z./z′ ratio) in many cases. The combination of AI-ECD and ECD promises to increase the confidence of mass spectrometry-based peptide sequencing and protein identification.

Original languageEnglish (US)
Pages (from-to)7596-7602
Number of pages7
JournalAnalytical Chemistry
Issue number20
StatePublished - Oct 15 2007
Externally publishedYes


ASJC Scopus subject areas

  • Analytical Chemistry

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