title: Solvent migration from the C- to the N-terminus of amino acid in photoionization of phenylglycine-water complex.
abstract: Photo-oxidation of amino acids is known to generate reactive protein radicals that lead to lethal disorders. We investigated photoionization of hydrated phenylglycine complexes in the gas phase and found that the excess internal energy from photoionization drives decarboxylation in competition with dehydration. We also found that, in decarboxylation, the solvent migrates a large distance from the C terminus of the neutral amino acid to the N terminus of the newly formed radical cation upon ionization, prior to the departure of the carboxyl group. It is noted that a solvent does not just act as a passive medium bound to the solute molecule but actively pursues its own course of action upon external perturbation that changes its chemical environment.
authors.affiliation: Department of Chemistry, Seoul National University, Seoul 151-747, Korea.
authors.forename: Hyung Min
authors.initials: HM
authors.lastname: Kim
authors.forename: Kyu Young
authors.initials: KY
authors.lastname: Han
authors.forename: Juyeon
authors.initials: J
authors.lastname: Park
authors.forename: Gap-Sue
authors.initials: GS
authors.lastname: Kim
authors.forename: Seong Keun
authors.initials: SK
authors.lastname: Kim
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry; D002412:Cations / Q000737:chemistry / Q000528:radiation effects*; D003653:Decarboxylation; D005609:Free Radicals / Q000737:chemistry / Q000528:radiation effects; D005998:Glycine / Q000031:analogs & derivatives* / Q000737:chemistry; D008958:Models, Molecular; D009584:Nitrogen / Q000737:chemistry; D010777:Photochemistry; D012997:Solvents / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D014867:Water / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D002412:Cations; D005609:Free Radicals; D012997:Solvents; D014867:Water; C008852:2-phenylglycine; D002244:Carbon; D009584:Nitrogen; D005998:Glycine