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Inhibition of the mitochondrial bc 1 complex by dibromothymoquinone
Author(s) -
Esposti Mauro Degli,
Rugolo Michela,
Lenaz Giorgio
Publication year - 1983
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(83)80238-5
Subject(s) - coenzyme q – cytochrome c reductase , ubiquinol , cytochrome c1 , cytochrome c oxidase , cytochrome , chemistry , cytochrome c , redox , respiratory chain , biochemistry , electron transport chain , cytochrome b , autoxidation , mitochondrial respiratory chain , electron transfer , stereochemistry , reductase , substrate (aquarium) , mitochondrion , enzyme , biology , photochemistry , inorganic chemistry , mitochondrial dna , gene , ecology
We have studied the effects of dibromothymoquinone (DBMIB) in various redox activities of the succinate—cytochrome c span of the mitochondrial respiratory chain. At concentrations higher than 50 mol/mol of cytochrome c 1 the inhibitor produces a bypass of electron transfer on the substrate side of the bc 1 complex, because of its autooxidation capability. This induces an artifactual overestimation of the real inhibition titer of the redox activity of this enzyme, which has been found to be 3–6 mol/mol of cytochrome c 1 by following the ubiquinol—cytochrome c reductase activity. This action is reversed by addition of excess of sulphydryl compounds like cysteine.