Effects of 2-hydroxy-3-undecyl-1,4-naphthoquinone on respiration of electron transport particles and mitochondria: topographical location of the Rieske iron-sulfur protein and the quinone binding site
- 13 September 1983
- journal article
- research article
- Published by American Chemical Society (ACS) in Biochemistry
- Vol. 22 (19) , 4394-4400
- https://doi.org/10.1021/bi00288a008
Abstract
2-Hydroxy-3-undecyl-1,4-naphthoquinone is a quinone analog that inhibits mitochondrial respiration in the cytochrome b-c1 region with an apparent Ki of 2.5 .times. 10-7 M. In [bovine heart] electron transport particles, it prevents the reduction of cytochrome c1 by succinate but not its oxidation by O2 and prevents oxidation of cytochrome b but not its reduction by succinate. The analog increases the amount of steady-state cytochrome b reduction in actively respiring particles. It inhibits oxidant-induced reduction of cytochrome b in the presence of antimycin. Inhibition of succinate oxidase activity in electron transport particles is independent of the pH of the suspending medium while at pH values above 8 with mitochondria, inhibition decreases. Since the apparent pK of the bound quinone is pH 6.6, the pH dependency of the inhibition is likely due to the pK of the Rieske Fe-S center (pH 8). The Rieske center and thus the quinone binding site are located on the cytoplasmic face of the inner membrane.Keywords
This publication has 1 reference indexed in Scilit:
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