193 nm photodissociation of larger multiply-charged biomolecules

Ziqiang Guan, Neil L. Kelleher, Peter B. O'Connor, David J. Aaserud, Daniel P. Little, Fred W. McLafferty*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

113 Scopus citations


In contrast to most ion dissociation methods, 193 nm ultraviolet photodissociation of electrosprayed melittin (2.8 kDa) and ubiquitin (8.6 kDa) molecular ions yields new c and z ions (backbone amine bond dissociation) that provide additional sequence information. Dissociation by collisions or infrared photons produce b and y ions; for cleavages between the same amino acids the c ion represents the addition of NH2 to the b ion, and z the loss of NH2 from the y ion, so that these ions can be differentiated by this ± 16.02 Da difference. However, 193 nm photodissociation of 12–29 kDa ions as yet does not give collectable product ions, and that of the very stable y182+ ion from ubiquitin only effects a side chain loss. 193 nm irradiation of negative ions of all-T 30-mer DNA appears to eject electrons; apparently this is the first observation of electron photodetachment from multiply-charged negative ions.

Original languageEnglish (US)
Pages (from-to)357-364
Number of pages8
JournalInternational Journal of Mass Spectrometry and Ion Processes
StatePublished - Jan 1 1996


  • 193 nm
  • Electrospray
  • Fourier transform ion cyclotron resonance
  • Photodissociation

ASJC Scopus subject areas

  • Spectroscopy


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