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Updated: May 24, 2026

Enrichment of Bacterial Lipoproteins and Preparation of N-terminal Lipopeptides for Structural Determination by Mass Spectrometry
Published on: May 21, 2018
Study of fragmentation pathways of metastable negative ions in aliphatic dipeptides using the statistical theory
P V Shchukin1, M V Muftakhov, A V Pogulay
1Institute of Molecules and Crystals Physics, Ufa Research Center of Russian Academy of Sciences, Prospekt Oktyabrya 151, 450075, Ufa, Russia. pavel@anrb.ru
Rationale:
Dipeptide molecules are good model systems for investigation of resonant reactions of low-energy electrons with proteins. The present work is devoted to the study of the processes of formation and fragmentation of negative ions in aliphatic dipeptides glycyl-glycine and glycyl-alanine. The metastable decays of negative ions were detected in these objects, and have been investigated with the aim of clarification of the mechanisms of fragmentation.
Methods:
The effective yield curves for negative ions as functions of electron energy were obtained using a magnetic sector mass spectrometer rebuilt for generation and detection of negative ions. For analysis of the observed metastable decays statistical and thermochemical approaches have been used.
Results:
The ions structures, the enthalpies of formation of neutral and charged particles, and the rate constants of dissociative reactions have been found.
Conclusions:
Comparison of the experimental results with theoretical data leads to the conclusion that metastable ion decay proceeds with minimal structural changes avoiding complicated rearrangements and isomerization processes.
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