%0 Journal Article %A Hodyss, Robert %A Cox, Heather A. %A Beauchamp, J. L. %D 2005 %T Bioconjugates for Tunable Peptide Fragmentation:  Free Radical Initiated Peptide Sequencing (FRIPS) %U https://acs.figshare.com/articles/journal_contribution/Bioconjugates_for_Tunable_Peptide_Fragmentation_Free_Radical_Initiated_Peptide_Sequencing_FRIPS_/3268198 %R 10.1021/ja052042z.s001 %2 https://acs.figshare.com/ndownloader/files/5105917 %K H atom abstraction %K CAD %K initiator Vazo 68 %K ECD fragmentation %K collisional activation %K II %K peptide backbone %K ion trap mass spectrometer %K type fragments %K peptide fragments %K protein sequencing %K FRIPS %X The free radical initiator Vazo 68 is coupled to a peptide and electrosprayed into an ion trap mass spectrometer. On collisional activation, the Vazo 68−peptide conjugate generates a free radical, which can be collisionally activated to cleave the peptide backbone. Mostly z-type fragments are formed, as in CAD of other radical peptides and ECD fragmentation. We present data for the Angiotensin II−Vazo 68 conjugate and discuss possible sites of H atom abstraction from the peptide. This experimental methodology for generating peptide fragments is a useful step toward the development of a completely gas-phase approach to protein sequencing. %I ACS Publications