title: Decomposition of methionine by low energy electrons.
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).
authors.affiliation: Department of Chemistry, Siedlce University, 3-Maja 54, 08-110 Siedlce, Poland. kopyra@uph.edu.pl
authors.forename: Janina
authors.initials: J
authors.lastname: Kopyra
authors.forename: Iwona
authors.initials: I
authors.lastname: Szamrej
authors.forename: Hassan
authors.initials: H
authors.lastname: Abdoul-Carime
authors.forename: Bernadette
authors.initials: B
authors.lastname: Farizon
authors.forename: Michel
authors.initials: M
authors.lastname: Farizon
mesh_terms: D004583:Electrons; D006878:Hydroxides / Q000737:chemistry; D008715:Methionine / Q000737:chemistry*; D013440:Sulfides / Q000737:chemistry*
chemical_list: D006878:Hydroxides; D013440:Sulfides; C031356:hydroxide ion; D008715:Methionine