Resonant electron capture by aspartame and aspartic acid molecules.
BACKGROUND
The processes for dissociative electron capture are the key mechanisms for decomposition of biomolecules, proteins in particular, under interaction with low-energy electrons. Molecules of aspartic acid and aspartame, i.e. modified dipeptides, were studied herein to define the impact of the side functional groups on peptide chain decomposition in resonant electron-molecular reactions.


METHODS
The processes of formation and decomposition of negative ions of both aspartame and aspartic acid were studied by mass spectrometry of negative ions under resonant electron capture. The obtained mass spectra were interpreted under thermochemical analysis by quantum chemical calculations.


RESULTS
Main channels of negative molecular ions fragmentation were found and characteristic fragment ions were identified.


CONCLUSIONS
The СООН fragment of the side chain in aspartic acid is shown to play a key role like the carboxyl group in amino acids and aliphatic oligopeptides. Copyright © 2016 John Wiley & Sons, Ltd.
Institute of Molecule and Crystal Physics, Ufa Research Centre of Russian Academy of Sciences, Prospect Octyabrya 151, Ufa, Russia.
M V
MV
Muftakhov
Institute of Molecule and Crystal Physics, Ufa Research Centre of Russian Academy of Sciences, Prospect Octyabrya 151, Ufa, Russia.
P V
PV
Shchukin
D001218:Aspartame / Q000737:chemistry*; D001224:Aspartic Acid / Q000737:chemistry*; D004151:Dipeptides / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods
D004151:Dipeptides; D007477:Ions; D001224:Aspartic Acid; D001218:Aspartame