A novel ubiquinone reductase activity in rat cytosol

FEBS Letters

Okamoto, Tadashi¹  Goshima, Kiyota²  Kishi, Takeo¹  Shitashige, Miki¹  Takahashi, Takayuki¹ 

[1] Faculty of Pharmaceutical Sciences, and Kobe-Gakuin University, Nishi-ku, Kobe, Japan;Faculty of Humanities and Sciences, Kobe-Gakuin University, Nishi-ku, Kobe, Japan

关键词: NAD(P)H;    DT-diaphorase;    Cytosol (rat liver);    Ubiquinone reductase;    Subcellular organelle;   

DOI  :  10.1016/0014-5793(92)81499-C

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Ubiquinone (UQ) reductase activity which reduces UQ to ubiquinol (UQH₂) in rat tissues was roughly proportional to the UQH₂/total UQ ratio in respective tissues. The honest activity was found in the liver, showing the highest UQH₂/total UQ ratio. A greater part of liver UQ reductase activity was located in the cytosol. Within a week, the liver UQ reductase activity decreased by 80% even at −20°C. The DT-diaphorase activity was stable. UQ reductase required NADPH as the hydrogen donor and was not inhibited by a less than 1μM concentration of dicoumarol. There was no stimulation of UQ reductase in the presence of bovine serum albumin nor in Triton X-100. Yet, both stimulated DT-diaphorase. As a result, UQ reductase appeared to be a novel NADPH-UQ oxidoreductase and responsible for the UQ redox state in liver.

【 授权许可】

Unknown