Document Detail

Antimycin-resistant alternate electron pathway to plastocyanin in bovine-heart complex III.
MedLine Citation:
PMID:  2989259     Owner:  NLM     Status:  MEDLINE    
Bovine-heart Complex III can catalyze the reduction of spinach plastocyanin by a decyl analog of ubiquinol-2 at a rate comparable with the rate of plastocyanin reduction by plastoquinol as catalyzed by the cytochrome b6-f complex purified from spinach leaves. This plastocyanin reduction as catalyzed by Complex III was almost completely inhibited by myxothiazol at stoichiometric concentrations, partially inhibited by UHDBT (5-n-undecyl-6-hydroxy-4,7-dioxobenzothiazole) and funiculosin, and was relatively insensitive to antimycin and HQNO (2-n-heptyl-4-hydroxyquinoline-N-oxide). Cytochrome c reduction as catalyzed by Complex III displayed a residual, inhibitor-insensitive rate of 5% of the uninhibited rate for each of the three inhibitors, antimycin, myxothiazol, and UHDBT. However, the residual rate that was insensitive to each of the inhibitors added singly was inhibited further by addition of the remaining two inhibitors. From these results it is concluded that plastocyanin reduction involves an electron-transfer pathway through Complex III that is distinct from the pathway utilized for reduction of cytochrome c.
B C Tripathy; J S Rieske
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of bioenergetics and biomembranes     Volume:  17     ISSN:  0145-479X     ISO Abbreviation:  J. Bioenerg. Biomembr.     Publication Date:  1985 Jun 
Date Detail:
Created Date:  1985-08-06     Completed Date:  1985-08-06     Revised Date:  2013-02-11    
Medline Journal Info:
Nlm Unique ID:  7701859     Medline TA:  J Bioenerg Biomembr     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  141-50     Citation Subset:  IM    
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MeSH Terms
Anthraquinones / pharmacology
Antimycin A / analogs & derivatives*,  pharmacology
Drug Resistance
Electron Transport
Electron Transport Complex III
Hydrogen-Ion Concentration
Hydroxyquinolines / pharmacology
Models, Chemical
Multienzyme Complexes / metabolism*
Myocardium / analysis*
NADH, NADPH Oxidoreductases / metabolism*
Plant Proteins / metabolism*
Plastocyanin / metabolism*
Quinone Reductases / metabolism*
Thiazoles / pharmacology
Grant Support
Reg. No./Substance:
0/Anthraquinones; 0/Hydroxyquinolines; 0/Methacrylates; 0/Multienzyme Complexes; 0/Plant Proteins; 0/Thiazoles; 11118-72-2/antimycin; 1FU5S5CG6A/2-(n-heptyl)-4-hydroxyquinoline N-oxide; 476-56-2/funiculosin (anthraquinone); 642-15-9/Antimycin A; 76706-55-3/myxothiazol; 9014-09-9/Plastocyanin; EC Transport Complex III; EC 1.6.-/NADH, NADPH Oxidoreductases; EC 1.6.99.-/Quinone Reductases

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

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