Quantitative decrease of human cytochrome c oxidase during development: evidences for a post-transcriptional regulation
- Lefai, Etienne
- Vincent, Annie
- Boespflug-Tanguy, Odile
- Tanguy, Alain
- Alziari, Serge
DOIAbstract
AbstractIn an earlier study, we showed that cytochrome c oxidase activity, measured in mitochondria isolated from human muscular biopsies, decreased steadily and substantially between the age of four years and adulthood (P<0.05), whereas complexes I and III activity remained constant. The present study investigates a number of possible causes for this change in activity: although there is a drop in the apparent Vmax, neither the apparent enzyme Km, nor the cellular mtDNA concentration shows any variations over the studied period. Steady-state concentrations of mitochondrial gene transcripts (CO I, CO II, CO III, but also 12S, cytochrome b, or ND4) increase within this age group, indicating an overall increase in mitochondrial genome express...
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