title: Photochemical properties and phototoxicity of Pazufloxacin: a stable and transient study.
abstract: Photochemical properties and phototoxicity of Pazufloxacin (PAX) were systematically investigated in aqueous solutions using UV-Vis, fluorescence, laser flash photolysis, pulse radiolysis and SDS-PAGE gel electrophoresis techniques. PAX triplet-state ((3)PAX(*)) absorption spectra (λ(max)=570 nm) was determined. (3)PAX(*) was quenched by PAX and O(2), with rate constants of 6.9×10(8) and 3.2×10(8) dm(3) mol(-1) s(-1), respectively. The pK(a) values (5.7 and 8.6) for the protonation equilibrium were determined by UV-Vis and fluorescence techniques. The PAX triplet energy (E(T)=260.3 kJ/mol) was obtained using energy transfer method. The reaction of electron transfer from tryptophan (TrpH) and dGMP to (3)PAX(*) was found with rate constants of 8.8×10(7) and 8.7×10(6) dm(3) mol(-1) s(-1), respectively. The rate constants for reactions of ()OH, SO(4)(-) and hydrated electron with PAX were found to be 5.8×10(8), 2.1×10(9) and 9×10(9)d m(3) mol(-1) s(-1), respectively. Based on the results obtained, a rational scheme for dGMP, TrpH and lysozyme photodamage induced by PAX was proposed.
authors.affiliation: Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, PR China.
authors.forename: Yancheng
authors.initials: Y
authors.lastname: Liu
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.forename: Haixia
authors.initials: H
authors.lastname: Li
authors.forename: Ruizhi
authors.initials: R
authors.lastname: Tang
authors.forename: Rong rong
authors.initials: Rr
authors.lastname: Cui
authors.forename: Wenfeng
authors.initials: W
authors.lastname: Wang
mesh_terms: D003848:Deoxyguanine Nucleotides / Q000737:chemistry; D004579:Electron Transport; D004591:Electrophoresis, Polyacrylamide Gel; D024841:Fluoroquinolones / Q000737:chemistry* / Q000528:radiation effects* / Q000633:toxicity; D007834:Lasers; D009113:Muramidase / Q000187:drug effects; D010078:Oxazines / Q000737:chemistry* / Q000528:radiation effects* / Q000633:toxicity; D055668:Photochemical Processes; D010782:Photolysis; D011675:Pulse Radiolysis; D014364:Tryptophan / Q000187:drug effects
chemical_list: D003848:Deoxyguanine Nucleotides; D024841:Fluoroquinolones; D010078:Oxazines; C078052:pazufloxacin; C007257:2'-deoxyguanosine 5'-phosphate; D014364:Tryptophan; D009113:Muramidase