Ceruloplasmin enhances DNA damage induced by cysteine/iron in vitro

Citation
Rh. Kim et al., Ceruloplasmin enhances DNA damage induced by cysteine/iron in vitro, BIOCHIMIE, 83(6), 2001, pp. 487-495
Citations number
53
Categorie Soggetti
Biochemistry & Biophysics
Journal title
BIOCHIMIE
ISSN journal
03009084 → ACNP
Volume
83
Issue
6
Year of publication
2001
Pages
487 - 495
Database
ISI
SICI code
0300-9084(200106)83:6<487:CEDDIB>2.0.ZU;2-C
Abstract
Ceruloplasmin (Cp) was found to promote the oxidative damage to DNA in vitr o, as evidenced by the formation of 8-hydroxy-2 ' -deoxyguanosine and stran d breaks, when incubated with a cysteine metal-catalyzed oxidation system ( Cys-MCO) comprised of Fe3+, O-2, and cysteine as an electron donor. The cap acity of Cp to enhance oxidative damage to DNA was inhibited by hydroxyl ra dical scavengers such as sodium azide and mannitol, a metal chelator, dieth ylenetriaminepentaacetic acid, a spin-trapping agent, 5,5-dimethyl-1-pyrrol ine N-oxide (DMPO) and catalase. Ceruloplasmin also caused the two-fold enh ancement of a mutation in the pUC18 lacZ ' gene in the presence of Cys-MCO when measured as a loss of a-complementation. Incubation of Cp with Cys-MCO resulted in an increase in the content of carbonyl groups and the signific ant alteration of the ferroxidase activity, as well as the proteolytic susc eptibility. The deoxyribose assay and the salicylate hydroxylation assay sh owed that hydroxyl free radicals were generated in the reaction of Cp with Cys-MCO. The release of a portion of Cu from Cp was observed, and conformat ional alterations were indicated by the changes in fluorescence spectra. Ba sed on these results, we interpret the enhancing effect of Cp on DNA damage and mutagenicity induced by Cys-MCO as due to reactive oxygen species, pro bably hydroxyl free radicals, formed by the reaction of free Cu2+, released from oxidatively damaged Cp, and H2O2 produced by Cys-MCO. The release of Cu from Cp during oxidative stress could enhance the formation of reactive oxygen species and could also potentiate cellular damage. (C) 2001 Societe francaise de biochimie et biologic moleculaire / Editions scientifiques et medicales Elsevier SAS. All rights reserved.