title: Dissociations of complexes between monovalent metal ions and aromatic amino acid or histidine.
abstract: The fragmentations of [AA + M](+) complexes, where AA = Phe, Tyr, Trp, or His, and M is a monovalent metal (Li, Na, or Ag), have been exhaustively studied through collision-induced dissociation (CID) and through deuterium labeling. Dissociations of the Li- and Ag-containing complexes gave a large number of fragment ions; by contrast, the sodium/amino acid complexes have lower binding energies, and dissociation resulted in much simpler spectra, with loss of the entire ligand dominating. Unambiguous assignments of these fragment ions were made and formation mechanisms are proposed. Of particular interest are fragmentations in which the charge was retained on the organic fragment and the metal was lost, either as a metal hydride (AgH) or hydroxide (LiOH) or as the silver atom (Ag(•)).
authors.affiliation: Department of Chemistry, The American University in Cairo, New Cairo, Egypt.
authors.forename: Tamer
authors.initials: T
authors.lastname: Shoeib
authors.forename: Junfang
authors.initials: J
authors.lastname: Zhao
authors.forename: Houssain
authors.initials: H
authors.lastname: Ei Aribi
authors.forename: Alan C
authors.initials: AC
authors.lastname: Hopkinson
authors.forename: K W Michael
authors.initials: KW
authors.lastname: Siu
mesh_terms: D024322:Amino Acids, Aromatic / Q000737:chemistry*; D000641:Ammonia / Q000737:chemistry; D002245:Carbon Dioxide / Q000737:chemistry; D002412:Cations / Q000737:chemistry; D041961:Deuterium Exchange Measurement; D006639:Histidine / Q000737:chemistry*; D008094:Lithium / Q000737:chemistry*; D008958:Models, Molecular; D012834:Silver / Q000737:chemistry*; D012964:Sodium / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D014867:Water / Q000737:chemistry
chemical_list: D024322:Amino Acids, Aromatic; D002412:Cations; D014867:Water; D002245:Carbon Dioxide; D012834:Silver; D006639:Histidine; D000641:Ammonia; D008094:Lithium; D012964:Sodium