Decomposition of methionine by low energy electrons

Phys Chem Chem Phys. 2012 Jun 14;14(22):8000-4. doi: 10.1039/c2cp40461c. Epub 2012 May 3.

Abstract

In this work, we present the results from low energy (<12 eV) electron impact on isolated methionine, Met. We show that dissociative electron attachment is the operative mechanism for the sulfur content amino-acid fragmentation. The two most dominant fragments are attributed to the (Met-H)(-) and (C(4)NOH(5))(-) ions that are formed at energy below 2 eV. The formation of the latter anion is accompanied by the loss of neutral counterparts, which are most likely a water molecule and highly toxic methanethiol, CH(3)SH. Further fragments are associated with the damage at the sulfur end of the amino acid, producing the methyl sulfide anion CH(3)S(-) or sulfur containing neutrals. In the context of radiation induced damage to biological material at the nano-scale level, the present interest of methionine arises from the implication of the molecule in biological processes (e.g., S-adenosyl methionine for the stimulation of DNA methyltransferase reactions or protein synthesis).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Electrons*
  • Hydroxides / chemistry
  • Methionine / chemistry*
  • Sulfides / chemistry*

Substances

  • Hydroxides
  • Sulfides
  • hydroxide ion
  • Methionine