Structures of mammalian cytosolic quinone reductases

Christine E. Foster, Mario A. Bianchet, Paul Talalay, Margarita Faig, L. Mario Amzel

Research output: Contribution to journalArticlepeer-review


The metabolism of quinone compounds presents one source of oxidative stress in mammals, as many pathways proceed by mechanisms that generate reactive oxygen species as by-products. One defense against quinone toxicity is the enzyme NAD(P)H:quinone oxidoreductase type 1 (QR1), which metabolizes quinones by a two-electron reduction mechanism, thus averting production of radicals. QR1 is expressed in the cytoplasm of many tissues, and is highly inducible. A closely related homologue, quinone reductase type 2 (QR2), has been identified in several mammalian species. QR2 is also capable of reducing quinones to hydroquinones, but unlike QR1, cannot use NAD(P)H. X-ray crystallographic studies of QR1 and QR2 illustrate that despite their different biochemical properties, these enzymes have very similar three- dimensional structures. In particular, conserved features of the active sites point to the close relationship between these two enzymes. (C) 2000 Elsevier Science Inc.

Original languageEnglish (US)
Pages (from-to)241-245
Number of pages5
JournalFree Radical Biology and Medicine
Issue number3-4
StatePublished - Aug 2000


  • Flavoprotein
  • Free radicals
  • Hydride transfer
  • Metalloprotein
  • NAD(P)H:quinone oxidocreductase

ASJC Scopus subject areas

  • Biochemistry
  • Physiology (medical)


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