title: Hydroxylation of 3-nitrotyrosine and its derivatives by gamma irradiation.
abstract: Radiation-induced hydroxylation of 3-nitrotyrosine (3-NY) and its derivatives in aqueous solution were investigated as a function of gamma-radiation dose. Irradiated 3-NY, 3-nitrotyrosine ethyl ester (3-NYE) and 3-NY containing peptide Gly-nitroTyr-Gly were separated and analyzed with reverse-phase HPLC and UV-Vis absorption spectroscopy. The structures of the hydroxylated products were confirmed by electrospray ionization mass spectrometry and (1)H-NMR spectrometry. The amounts of the hydroxylated products in irradiated 3-NY and Gly-nitroTyr-Gly solutions increased with increasing radiation dose. Tandem electrospray ionization mass spectrometry (ESI-Mass(2)) was performed to investigate the hydroxylation of peptide Gly-nitroTyr-Gly. These studies showed that the hydroxylation occurred at 3-NY residue. We also found that the identification of 3-NY hydroxylation in peptide could be identified by ion scanning for the specific immonium ion at m/z 197.0.
authors.affiliation: Key Laboratory of Bioorganic Phosphorous Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, PR China.
authors.forename: Wei-Qun
authors.initials: WQ
authors.lastname: Shi
authors.forename: Jun-Chen
authors.initials: JC
authors.lastname: Dong
authors.forename: Yu-Fen
authors.initials: YF
authors.lastname: Zhao
authors.forename: Yan-Mei
authors.initials: YM
authors.lastname: Li
mesh_terms: D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D017665:Hydroxyl Radical / Q000737:chemistry* / Q000528:radiation effects*; D006900:Hydroxylation / Q000528:radiation effects; D011829:Radiation Dosage; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry / Q000528:radiation effects
chemical_list: D017665:Hydroxyl Radical; C002744:3-nitrotyrosine; D014443:Tyrosine