title: UV photolysis of 3-nitrotyrosine generates highly oxidizing species: a potential source of photooxidative stress.
abstract: Laser flash photolysis at 266 nm of 3-nitrotyrosine and N-acetyl-3-nitrotyrosine ethyl ester generates an oxidizing species, which shows all of the characteristics of a hydroxyl radical. This species reacts with Br(-) to yield Br(2).-, via an intermediate, that is kinetically identified as HOBr.-. Moreover, the formation of Br(2).- can be suppressed by methanol; competition kinetics yield relative rate constants for the reaction of the reactive species with Br(-) and methanol that are similar to those for the hydroxyl radical. Parallel time-resolved UV/vis spectroscopy suggests the formation of phenoxyl radicals, consistent with the formation of hydroxyl radicals. Laser flash photolysis at 355 nm also generates reactive intermediates that oxidize Br(-) to Br(2).- but appear not to be hydroxyl radicals.
authors.affiliation: Laboratory for Inorganic Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Nauser
authors.forename: Willem H
authors.initials: WH
authors.lastname: Koppenol
authors.forename: Jill
authors.initials: J
authors.lastname: Pelling
authors.forename: Christian
authors.initials: C
authors.lastname: Schöneich
mesh_terms: D006863:Hydrogen-Ion Concentration / Q000528:radiation effects; D017665:Hydroxyl Radical / Q000528:radiation effects*; D007700:Kinetics; D018384:Oxidative Stress / Q000528:radiation effects; D010782:Photolysis; D017382:Reactive Oxygen Species / Q000528:radiation effects; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D017382:Reactive Oxygen Species; D017665:Hydroxyl Radical; C002744:3-nitrotyrosine; D014443:Tyrosine; C024960:nitrotyrosine ethyl ester