title: The peroxidase activity of bleomycin-Fe3+ is associated with damage to biological components.
abstract: In this study, bleomycin-Fe(3+) steadily oxidized tetramethylbenzidine (TMB) in the presence of peroxides. However, the ability of bleomycin-Fe(3+) to function as a peroxidase was extremely low compared with that of other peroxidases. A characteristic property of bleomycin-Fe(3+) different from that observed for other peroxidases is its ability to oxidize TMB at the similar rate at both a pH 5 and 8 in the presence of lipid hydroperoxide (LOOH). In the present experiments, hydroxyl radicals (HO•) were generated only when bleomycin-Fe(3+) was incubated with H2O2 at a pH of 5. No generation of HO• was observed during the incubation of bleomycin-Fe(3+) with LOOH. Meanwhile, bleomycin-Fe(3+) induced the formation of LOOH from linoleic acid and alcohol dehydrogenase was inactivated by bleomycin-Fe(3+) with peroxides. Thiobarbituric acid reactive substances were formed from DNA by bleomycin-Fe(3+) with H2O2, and strand breaks were caused by bleomycin-Fe(3+) with LOOH. The oxidative substrates for bleomycin-Fe(3+) blocked the damage to biological components induced by bleomycin-Fe(3+). These results suggest that compound I-like species contribute to the process of damage to biological components induced by bleomycin-Fe(3+).
authors.affiliation: Department of Natural Science in Hokkaido Pharmaceutical University School of Pharmacy, Katsuraoka-cho 7-1, Otaru 0470264, Japan miurat@hokuyakudai.ac.jp.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Miura
mesh_terms: D001560:Benzidines / Q000378:metabolism; D001761:Bleomycin / Q000494:pharmacology*; D004249:DNA Damage / Q000187:drug effects; D004587:Electrophoresis, Agar Gel; D005290:Ferric Compounds / Q000737:chemistry / Q000494:pharmacology*; D006861:Hydrogen Peroxide / Q000378:metabolism; D010084:Oxidation-Reduction / Q000187:drug effects
chemical_list: D001560:Benzidines; D005290:Ferric Compounds; D001761:Bleomycin; C020515:N,N,N',N'-tetramethylbenzidine; D006861:Hydrogen Peroxide
keywords: bleomycin-Fe3+; compound I-like species; hydroxyl radical; lipid hydroperoxide; peroxidase