Skip directly to search Skip directly to A to Z list Skip directly to page options Skip directly to site content

NIOSHTIC-2 Publications Search

Search Results

Cobalt-mediated generation of reactive oxygen species and its possible mechanism.

Authors
Leonard-S; Gannett-PM; Rojanasakul-Y; Schwegler-Berry-D; Castranova-V; Vallyathan-V; Shi-X
Source
J Inorg Biochem 1998 Jul; 70(3-4):239-244
NIOSHTIC No.
20025482
Abstract
Electron spin resonance spin trapping was utilized to investigate free radical generation from cobalt (Co) mediated reactions using 5,5-dimethyl-1-pyrroline (DMPO) as a spin trap. A mixture of Co with water in the presence of DMPO generated 5,5-dimethylpyrroline-(2)-oxy(1) DMPOX, indicating the production of strong oxidants. Addition of superoxide dismutase (SOD) to the mixture produced hydroxyl radical (OH). Catalase eliminated the generation of this radical and metal chelators, such as desferoxamine, diethylenetriaminepentaacetic acid or 1,10-phenanthroline, decreased it. Addition of Fe(II) resulted in a several fold increase in the OH generation. UV and O2 consumption measurements showed that the reaction of Co with water consumed molecular oxygen and generated Co(II). Since reaction of Co(II) with H2O2 did not generate any significant amount of OH radicals, a Co(I) mediated Fenton-like reaction [Co(I) + H2O2-->Co(II) + OH + OH-] seems responsible for OH generation. H2O2 is produced from O2.- via dismutation, O2- is produced by one-electron reduction of molecular oxygen catalyzed by Co. Chelation of Co(II) by biological chelators, such as glutathione or beta-ananyl-3-methyl-L-histidine alters, its oxidation-reduction potential and makes Co(II) capable of generating OH via a Co(II)-mediated Fenton-like reaction [Co(II) + H2O2-->Co(III) + OH + OH-]. Thus, the reaction of Co with water, especially in the presence of biological chelators, glutathione, glycylglycylhistidine and beta-ananyl-3-methyl-L-histidine, is capable of generating a whole spectrum of reactive oxygen species, which may be responsible for Co-induced cell injury.
Keywords
Cobalt-compounds; Oxidation; Chelating-agents; Cell-damage; Metal-oxides; Metal-compounds; Analytical-processes; Analytical-chemistry
Contact
Pathology and Physiology Research Branch, National Institute for Occupational Safety and Health, Morgantown, WV 26505
CODEN
JIBIDJ
Publication Date
19980701
Document Type
Journal Article
Email Address
xas0@cdc.gov
Fiscal Year
1998
NTIS Accession No.
NTIS Price
Issue of Publication
3-4
ISSN
0162-0134
NIOSH Division
HELD
Source Name
Journal of Inorganic Biochemistry
State
WV
TOP