Inhibition of the mitochondrial bc 1 complex by dibromothymoquinone

FEBS Letters

Lenaz, Giorgio¹  Rugolo, Michela¹  Esposti, Mauro Degli¹ 

[1] Institute of Botany, University of Bologna, Via Irnerio 42, 40126 Bologna, Italy

关键词: Dibromothymoquinone;    Ubiquinol—cytochrome c oxidoreductase (bc1 complex);    Mitochondria;    Respiratory chain;    Iron—sulphur protein;    DBMIB;    2;    5-dibromo-3-methyl-6-isopropylbenzoquinone;    DCIP;    dichlorophenolindophenol;    EDTA;    ethylendiaminotetraacetate;    EPR;    electron paramagnetic resonance;    Qo;    2;    3-dimethoxy-5-methylbenzoquinone;    Q1;    ubiquinone-1;    Q1H2 Q3H2;    ubiquinol-1 and ubiquinol-3;    TTFA;    thenoyltrifluoroacetone;    UHDBT;    5-n-undecyl-4;    7-dioxobenzothiazole;   

DOI  :  10.1016/0014-5793(83)80238-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

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.

【 授权许可】

Unknown