Exogenous quinones directly inhibit the respiratory NADH dehydrogenase in Escherichia coli

James Imlay, Irwin Fridovich

Research output: Contribution to journalArticlepeer-review


The ability of naphthoquinones to generate reactive oxygen species has been widely exploited in studies of oxidative stress. However, excess superoxide dismutase and catalase failed to protect Escherichia coli in rich medium against growth inhibition by plumbagin, indicating that its toxic effect was not due to the production of partially reduced oxygen species. Respiration failed immediately upon the addition of growth-inhibitory levels of plumbagin. Studies in vitro showed that plumbagin and other redox-active quinones intercept electrons from NADH dehydrogenase, the primary respiratory dehydrogenase in glucose-containing media. An excess of oxidative substrate, such as plumbagin, inactivates this enzyme, which appears to be redox-regulated. The resultant respiratory arrest is a cautionary example of metabolic dysfunction from redox-cycling drugs that cannot be attributed to superoxide or hydrogen peroxide.

Original languageEnglish (US)
Pages (from-to)337-346
Number of pages10
JournalArchives of Biochemistry and Biophysics
Issue number1
StatePublished - Jul 1992
Externally publishedYes

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology


Dive into the research topics of 'Exogenous quinones directly inhibit the respiratory NADH dehydrogenase in Escherichia coli'. Together they form a unique fingerprint.

Cite this