Photoinduced fragmentation of gas-phase protonated leucine- enkephalin peptide in the VUV range

M Lj Ranković,A Giuliani,A R Milosavljević,F Canon,L Nahon

doi:10.1088/1742-6596/635/1/012034

Abstract

In this article we report new results for action spectroscopy of protonated peptide Leucine enkephalin (YGGFL). By coupling a linear ion trap mass spectrometer with a vacuum ultraviolet (VUV) synchrotron radiation beamline, we investigate photofragmentation pattern of this peptide, through the analysis of tandem mass spectra recorded over a range of VUV photon energies, below and above the ionization energy. The obtained fragmentation patterns are discussed and compared to previous results.

Highlights

Development of electrospray ionization (ESI) [1], along with the advances in mass spectrometry techniques in recent years, has allowed manipulation of large bio-molecular ionic species in the gas phase
Sztáray et al in [15] performed a review of the studies about Leucine enkephalin (Leu-enk) energetics and reaction pathways, so we will focus here only on the discussion of the most prominent fragments prevailing under our experimental conditions
The ionization energy (IE) of protonated Leu-enk was determined by DFT calculations to be 8.87 eV [16]

Summary

Introduction

Development of electrospray ionization (ESI) [1], along with the advances in mass spectrometry techniques in recent years, has allowed manipulation of large bio-molecular ionic species in the gas phase. The reported results include collision induced dissociation (CID) [3], surface induced dissociation (SID) [4], blackbody infrared radiative dissociation (BIRD) [5] and laserinduced dissociation (LID) [6] Each of these methods produces different conditions which favor certain decomposition pathways governed by certain fragmentation mechanisms. One of the reasons Leu-enk is used as a standard peptide is because it is very useful for testing and tuning new experimental setups, since it has been found that abundance ratios of some fragment ions can indicate an amount of internal energy deposited in the precursor ions [7]. We extend this investigation by means of mass resolution, the number of assigned ionic fragments and the photon energy range.

Experiment

Results and discussion

Conclusions

Methods