title: Damage of aromatic amino acids by the atmospheric free radical oxidant NO3˙ in the presence of NO2˙, N2O4, O3 and O2.
abstract: Analysis of the products formed in the reaction of NO(3)˙ with the N- and C-protected aromatic amino acids 1-5, which was performed under conditions that simulate exposure of biosurfaces to environmental pollutants, revealed insight how this important atmospheric free-radical oxidant can cause irreversible damage. In general, NO(3)˙ induced electron transfer at the aromatic ring is the exclusive initial pathway in a multi-step sequence, which ultimately leads to nitroaromatic compounds. In the reaction of NO(3)˙ with tryptophan 5 tricyclic products 12 and 13 are formed through an intramolecular, oxidative cyclization involving the amide moiety. In addition to this, strong indication for formation of N-nitrosamides was obtained, which likely result from reaction with N(2)O(4) through an independent non-radical pathway.
authors.affiliation: ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Chemistry and BIO21 Molecular Science and Biotechnology Institute, The University of Melbourne, 30 Flemington Road, Parkville, VIC 3010, Australia.
authors.forename: Catrin
authors.initials: C
authors.lastname: Goeschen
authors.forename: Natalia
authors.initials: N
authors.lastname: Wibowo
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: White
authors.forename: Uta
authors.initials: U
authors.lastname: Wille
mesh_terms: D024322:Amino Acids, Aromatic / Q000737:chemistry*; D005609:Free Radicals / Q000737:chemistry; D015394:Molecular Structure; D016877:Oxidants / Q000737:chemistry*
chemical_list: D024322:Amino Acids, Aromatic; D005609:Free Radicals; D016877:Oxidants