Fluidizing effect of endogenous ubiquinone in bovine heart mitochondrial membranes

Ubiquinone binding domains in bovine heart mitochondrial cytochrome b.

Cytochrome b was identified as one of the ubiquinone-binding proteins in bovine heart mitochondrial ubiquinol-cytochrome c reductase by photoaffinity labeling using 3-azido-2-methyl-5-methoxy-6-(3,7-dimethyl[3H]-octyl)-1,4-benzoquinone ([3H]azido-Q). The [3H]azido-Q-labeled cytochrome b protein was purified to homogeneity from the azido-Q-labeled ubiquinol-cytochrome c reductase by a procedure ...

Protein-ubiquinone interaction in bovine heart mitochondrial succinate-cytochrome c reductase. Synthesis and biological properties of fluorine substituted ubiquinone derivatives.

To investigate the protein-ubiquinone interaction in the bovine heart mitochondrial succinate-cytochrome c reductase region of the respiratory chain, three fluorine substituted ubiquinone derivatives, 2,3-dimethoxy-6-(9'-fluorodecyl)-1,4-benzoquinone (9FQ), 2-methoxy-5-trifluoromethyl-6-decyl-1,4-benzoquinone (TFQ), and 2-methoxy-5-trifluoromethyl-6-(9'-fluorodecyl)-1,4-benzoquinone (9FTFQ), we...

Ubiquinone Reductase from Bovine Heart Mitochondria

The molecular morphology of bovine heart mitochondrial NADH-ubiquinone reductase. Cross-linking with dithiobis(succinimidyl propionate).

The molecular morphology of NADH-ubiquinone reductase (complex I) was investigated by cross-linking with the cleavable bifunctional reagent, dithiobis(succinimidyl propionate). Cross-linking inhibits the following activities of the complex--NADH----3-acetylpyridine adenine dinucleotide (oxidized), NADH----2,6-dichloroindophenol, NADH----ferricyanide, and NADH----menadione--to different degrees ...

Specific labelling of a constituent polypeptide of bovine heart mitochondrial reduced nicotinamide-adenine dinucleotide-ubiquinone reductase by the inhibitor diphenyleneiodonium.

1. NADH-ubiquinone-1 and NADH-menadione reductase activities of Complex I were inhibited by diphenyleneiodonium (apparent Ki 23 and 30 nmol/mg of protein respectively). Reduction of K3Fe(CN)6 and juglone was relatively unaffected. 2. Iodoniumdiphenyl and derivatives were much less effective inhibitors. Compounds with similar ring structures to diphenyleneiodonium, in particular dibenzofuran, we...