Partial reversion of the electrogenic reaction in the ubiquinol

FEBS Letters

Mamedov, Mahir D.¹  Shinkarev, Vladimir P.²  Semenov, Alexey Yu.¹  Drachev, Lel A.¹  Mulkidjanian, Armen Ya.¹  Verkhovsky, Michael I.¹ 

[1] A.N. Belozersky Laboratory of Molecular Biology and Bioorganic Chemistry Moscow State University, Moscow, USSR;Biophysics Section, Department of Biology, Moscow State University, Moscow, USSR

关键词: bc 1-Complex;    Electrogenesis;    Ubiquinone;    Rhodobacter sphaeroides;   

DOI  :  10.1016/0014-5793(90)80825-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The interaction of the photosynthetic reaction center (RC)-generated ubiquinol with the ubiquinone-reducing center C of ubiquinol:cytochrome c ₂-oxidoreductase (bc ₁ -complex) has been studied electrometrically in Rhodobacter sphaeroides chromatophores. The addition of myxothiazol inhibited the ubiquinol-oxidizing center Z, suppressing the phases of membrane potential generation by the bc ₁,-complex, but at the same time induced an electrogenic phase of opposite polarity, sensitive to antimycin A, the inhibitor of center C. The rise time of this reverse phase varied from 3 ms at pH 6.0 to 1 ms at pH 9.5. At pH > 9.5 the reverse phase was limited by the rate of ubiquinol formation in RC. The magnitude of the reverse phase was constant within the pH range 7.5–10.0. It is assumed that the reverse phase is due to the electrogenic deprotonation reaction which takes place after the binding of the RC-generated ubiquinol to center C.

【 授权许可】

Unknown