2‐Nitrosofluorene and N‐hydroxy‐2‐aminofluorene react with the ubiquinone‐reduction center (center N) of the mitochondrial cytochrome bc 1 complex

FEBS Letters

Brandt, Ulrich¹  Klöhn, Peter-Christian²  Neumann, Hans-Günter² 

[1] Zentrum der Biologischen Chemie, Universität Frankfurt, Frankfurt, Germany;Institut für Toxikologie, Universität Würzburg, Versbacher Str. 9, 97078 Würzburg, Germany

关键词: Cytochrome bc 1 complex;    Cytochrome b;    2-Nitrosofluorene;    N-Hydroxy-2-aminofluorene;    Mitochondria (rat liver);    AA;    antimycin A;    AAF;    2-acetylaminofluorene;    FCCP;    carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone;    Myxo;    myxothiazol;    MOA;    E-β-methoxyacrylate stilbene;    NBH;    nonylubihydroquinone (2;    3-dimethoxy-6-methyl-5-nonylbenzohydroquinone);    NOF;    2-nitrosofluorene;    N-OH-AF;    N-hydroxy-2-aminofluorene;    Succ;    succinate;    TMPD;    N;    N;    N′;    N′-tetramethyl-p-phenylenediamine;    TTFA;    thenoyltrifluoroacetone;   

DOI  :  10.1016/0014-5793(96)00592-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

We determined the sites of artificial electron transfer onto 2-nitrosofluorene (NOF), a metabolite of carcinogenic 2-acetylaminofluorene in mitochondria and isolated cytochrome bc ₁ complex. NOF-induced O₂ consumption in mitochondria was sensitive to antimycin A, but insensitive to myxothiazol. In the isolated cytochrome bc ₁ complex, NOF induced rapid MOA-stilbene-insensitive reoxidation of cytochrome b, whereas in the presence of antimycin A, reoxidation was very slow. The corresponding hydroxylamine, N-hydroxy-2-aminofluorene (N-OH-AF), reduced cytochrome b specifically through center N of the cytochrome bc ₁ complex. We conclude that NOF and N-OH-AF bind to center N of the cytochrome bc ₁ complex and acts as electron acceptor and donor, respectively. The N-OH-AF/NOF interconversion is considered to be involved in the cytotoxicity of 2-acetylaminofluorene in vivo.

【 授权许可】

Unknown