| Mobilization of iron from crocidolite asbestos by certain chelators results in enhanced crocidolite-dependent oxygen consumption. | |
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MedLine Citation:
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PMID: 1654807 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The reactivity of iron on crocidolite asbestos with dioxygen was determined and compared with iron mobilized from crocidolite. Ferrozine, a strong Fe(II) chelator, was used to demonstrate that iron on crocidolite was redox active. More Fe(II) was mobilized from crocidolite (1 mg/ml) by ferrozine anaerobically (11.2 nmol/mg crocidolite/h) than aerobically (6.6 nmol/mg/h) in 50 mM NaCl, pH 7.5, suggesting that Fe(II) on crocidolite reacts with O2 upon aqueous suspension. However, suspension of crocidolite in 50 mM NaCl, pH 7.5, did not result in a measurable amount of O2 consumption. The addition of reducing agents (1 mM) increased the amount of Fe(II) on crocidolite, and addition of ascorbate resulted in 0.4 nmol O2 consumed/mg crocidolite/min. Therefore, iron on crocidolite had limited redox activity in the presence of ascorbate. However, mobilization of iron from crocidolite increased its redox activity. Citrate, nitrilotriacetate (NTA), or EDTA (1 mM) mobilized 79, 32, or 58 microM iron, respectively, in preincubations up to 76 h, and increased O2 consumption upon addition of ascorbate to 2.8, 7.6, or 22.0 nmol O2 consumed/mg/min, respectively. This activity depended only upon the presence of a component(s) mobilized from crocidolite by the chelators. Pretreatment of crocidolite with the iron chelator desferrioxamine B (10 mM) inhibited O2 consumption. The results of the present study suggest that iron on or in crocidolite is responsible for the redox activity of crocidolite, but that mobilization of iron by chelators such as citrate, NTA, or EDTA greatly enhances its redox activity. Thus, iron mobilization from crocidolite in vivo by low-molecular-weight chelators may lead to the increased production of reactive oxygen species which may damage biomolecules, such as DNA. |
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Authors:
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L G Lund; A E Aust |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Archives of biochemistry and biophysics Volume: 287 ISSN: 0003-9861 ISO Abbreviation: Arch. Biochem. Biophys. Publication Date: 1991 May |
Date Detail:
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Created Date: 1991-10-24 Completed Date: 1991-10-24 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0372430 Medline TA: Arch Biochem Biophys Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 91-6 Citation Subset: IM |
Affiliation:
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Department of Chemistry and Biochemistry, Utah State University, Logan 84322-0300. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Anaerobiosis Asbestos / chemistry* Asbestos, Crocidolite Ascorbic Acid / chemistry Chelating Agents / chemistry* Iron / chemistry* Kinetics Oxidation-Reduction Oxygen / chemistry* |
| Chemical | |
Reg. No./Substance:
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0/Chelating Agents; 12001-28-4/Asbestos, Crocidolite; 1332-21-4/Asbestos; 50-81-7/Ascorbic Acid; 7439-89-6/Iron; 7782-44-7/Oxygen |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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