Abstract |
Measurement of complex III activity is critical to the diagnosis of human mitochondrial disease and the study of mitochondrial pathobiology. Activity is measured as the maximal rate of antimycin A-sensitive reduction of exogenous cytochrome c by detergent-solubilized mitochondria. Complex III activity exhibited an unexpected variation based upon the commercial source of cytochrome c owing to an increase in the antimycin A-insensitive background reduction of cytochrome c and variable increases in total activity. Analysis of cytochrome c (producing a high-background) by fast protein liquid chromatography yielded a contaminant peak containing a lipid extractable component with redox spectra and mass spectroscopy fragmentation suggestive of a quinol. Measurement of inhibitor-sensitive rates are critical for the accurate and reproducible measurement of complex III activity and serve as a key quality control to screen for non-enzymatic reactions that obscure complex III activity.
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Authors | Shadi Moghaddas, Anne M Distler, Charles L Hoppel, Edward J Lesnefsky |
Journal | Mitochondrion
(Mitochondrion)
Vol. 8
Issue 2
Pg. 155-63
(Mar 2008)
ISSN: 1567-7249 [Print] Netherlands |
PMID | 18272433
(Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, U.S. Gov't, Non-P.H.S.)
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Chemical References |
- Hydroquinones
- Antimycin A
- Cytochromes c
- Electron Transport Complex III
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Topics |
- Antimycin A
(pharmacology)
- Chromatography, Liquid
(methods)
- Cytochromes c
(chemistry, standards)
- Drug Contamination
- Electron Transport Complex III
(analysis, metabolism)
- Hydroquinones
(analysis)
- Mass Spectrometry
- Mitochondria
(metabolism)
- Oxidation-Reduction
- Reproducibility of Results
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