The interaction of Q analogs, particularly hydroxydecyl benzoquinone (idebenone), with the respiratory complexes of heart mitochondria

Arch Biochem Biophys. 1996 Jun 15;330(2):395-400. doi: 10.1006/abbi.1996.0267.


We have studied the interaction of idebenone (2,3-dimethoxy-5-methy-6-(10-hydroxy)decyl-1,4-benzoquinone) with the energy-conserving complexes of the respiratory chain in beef heart mitochondria and compared its energetic efficiency with that of other analogs of coenzyme Q. Idebenone is a very effective substrate for succinate:Q reductase and ubiquinol:cytochrome c reductase, but it is clearly a poor substrate for NADH:Q reductase (complex I). Indeed, idebenone is a strong inhibitor of both the redox and proton pumping activity of complex I, showing effects in part similar to those of coenzyme Q-2. However, the mechanism of idebenone interaction with complex I may be different from that of Q-2 because of its different sensitivity to inhibitors. The possible relevance of the present findings to the therapeutic use of idebenone is discussed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Benzoquinones / metabolism*
  • Benzoquinones / pharmacology
  • Cattle
  • Electron Transport / drug effects
  • Energy Metabolism
  • Enzyme Inhibitors / pharmacology
  • In Vitro Techniques
  • Mitochondria, Heart / drug effects
  • Mitochondria, Heart / metabolism*
  • NAD(P)H Dehydrogenase (Quinone) / antagonists & inhibitors
  • NAD(P)H Dehydrogenase (Quinone) / metabolism
  • Oxidation-Reduction
  • Substrate Specificity
  • Ubiquinone / analogs & derivatives*
  • Ubiquinone / metabolism
  • Ubiquinone / pharmacology


  • Benzoquinones
  • Enzyme Inhibitors
  • Ubiquinone
  • NAD(P)H Dehydrogenase (Quinone)
  • idebenone