https://doi.org/10.1140/epjd/e2014-40826-y
Regular Article
VUV photofragmentation of protonated leucine-enkephalin peptide dimer below ionization energy*
1 Institute of Physics Belgrade,
University of Belgrade, Pregrevica
118, 11080
Belgrade,
Serbia
2 INRA, UMR1324 Centre des Sciences du
Goût et de l’Alimentation, 21000
Dijon,
France
3 Synchrotron SOLEIL, L’Orme des
Merisiers, Saint-Aubin, 91192
Gif-sur-Yvette,
France
4 UAR 1008 CEPIA, INRA,
44316
Nantes,
France
a
e-mail: vraz@ipb.ac.rs
Received:
23
December
2013
Received in final form:
28
January
2014
Published online:
25
March
2014
The experimental investigation of 5–8 eV photons induced dissociation of the leucine-enkephalin (Leu-Enk) peptide dimer, performed by coupling a linear ion trap with a synchrotron beamline, in combination with the tandem mass spectrometry, has been reported. The present work extends the existing results on Leu-Enk VUV-induced dissociation to lower sub-ionization photon energy range. The measured tandem mass spectra show that even at the photon energies below the ionization threshold, VUV irradiation of the protonated Leu-Enk dimer precursor can lead to a rich fragmentation pattern, including peptide sequence ions and neutral losses. The photodissociation yields of selected ionic fragments reveal the absorption bands at about 6.7–7.1 eV (185–175 nm). The experimental results have been supported by theoretical description of the [2Leu-Enk + H]+ precursors, optimized at B3LYP/6-31+G(d,p) level of DFT.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2014