Document Detail

Mitochondrial production of oxygen radical species and the role of Coenzyme Q as an antioxidant.
MedLine Citation:
PMID:  12709577     Owner:  NLM     Status:  MEDLINE    
The mitochondrial respiratory chain is a powerful source of reactive oxygen species (ROS), which is considered as the pathogenic agent of many diseases and of aging. We have investigated the role of complex I in superoxide radical production and found by the combined use of specific inhibitors of complex I that the one-electron donor to oxygen in the complex is a redox center located prior to the sites where three different types of Coenzyme Q (CoQ) competitors bind, to be identified with an Fe-S cluster, most probably N2, or possibly an ubisemiquinone intermediate insensitive to all the above inhibitors. Short-chain Coenzyme Q analogs enhance superoxide formation, presumably by mediating electron transfer from N2 to oxygen. The clinically used CoQ analog, idebenone, is particularly effective, raising doubts on its safety as a drug. Cells counteract oxidative stress by antioxidants. CoQ is the only lipophilic antioxidant to be biosynthesized. Exogenous CoQ, however, protects cells from oxidative stress by conversion into its reduced antioxidant form by cellular reductases. The plasma membrane oxidoreductase and DT-diaphorase are two such systems, likewise, they are overexpressed under oxidative stress conditions.
Maria Luisa Genova; Milena Merlo Pich; Annalisa Biondi; Andrea Bernacchia; Anna Falasca; Carla Bovina; Gabriella Formiggini; Giovanna Parenti Castelli; Giorgio Lenaz
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Review    
Journal Detail:
Title:  Experimental biology and medicine (Maywood, N.J.)     Volume:  228     ISSN:  1535-3702     ISO Abbreviation:  Exp. Biol. Med. (Maywood)     Publication Date:  2003 May 
Date Detail:
Created Date:  2003-04-23     Completed Date:  2003-06-12     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  100973463     Medline TA:  Exp Biol Med (Maywood)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  506-13     Citation Subset:  IM    
Dipartimento di Biochimica "G Moruzzi", University of Bologna, 40126 Bologna, Italy.
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MeSH Terms
Antioxidants / metabolism*
Binding Sites
Electron Transport / physiology
Electron Transport Complex I
Mitochondria / metabolism*
NADH, NADPH Oxidoreductases / metabolism
Reactive Oxygen Species / metabolism*
Ubiquinone / metabolism*
Reg. No./Substance:
0/Antioxidants; 0/Reactive Oxygen Species; 1339-63-5/Ubiquinone; EC 1.6.-/NADH, NADPH Oxidoreductases; EC Transport Complex I

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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