Inhibition of mitochondrial electron transport by hydroxy-substituted 1,4-quinones.
Mitochondrial electron transport from NADH, succinate, or duroquinol to oxygen is inhibited by 5-omega-cyclohexyl-n-pentyl-6-hydroxy-2,3-dimethoxy-1,4-benzoquinone and 2-omega-cyclohexyl-n-pentyl-3-hydroxy-1,4-napthoquinone. Assays of partial electron transport activities indicate a site of inhibition in the region between the site of duroquinol oxidation and cytochrome c reduction. Effects of the inhibitors on cytochrome spectra indicate the principle site of inhibition is between cytochromes of the b group and cytochrome c1. The quinones do not induce increased reduction of the b566 as does antimycin A. The benzoquinone can induce a partial antimycin insensitive bypass of the cytochromes b-c1 region. Uncoupling agents do not affect the extent of inhibition as has been reported for analogous naphthoquinone inhibitors.
D000818:Animals; D000963:Antimetabolites / Q000494:pharmacology; D002417:Cattle; D002738:Chloroquine / Q000494:pharmacology; D003579:Cytochrome Reductases / Q000378:metabolism; D004579:Electron Transport; D066298:In Vitro Techniques; D008931:Mitochondria, Muscle / Q000187:drug effects / Q000378:metabolism*; D009206:Myocardium; D010088:Oxidoreductases / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects; D011809:Quinones / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D013385:Succinate Dehydrogenase / Q000378:metabolism
D000963:Antimetabolites; D011809:Quinones; D002738:Chloroquine; D010088:Oxidoreductases; D013385:Succinate Dehydrogenase; D003579:Cytochrome Reductases