Dioxygen and temperature dependence of ubiquinone formation in Escherichia coli: studies of cells charged with 2-octaprenyl phenol

Eur J Biochem. 1978 Sep 15;90(1):107-12. doi: 10.1111/j.1432-1033.1978.tb12580.x.


The multiple aromatic auxotroph Escherichia coli K-12 strain AB 2847 (aroB-) was conditioned for efficient ubiquinone-8 formation. Resting cells readily convert 4-hydroxy[U-14C]benzoate into ubiquinone-8 (60 nmol per g wet weight). Under argon this processing stops at the stage of 2-octaprenyl phenol. Only upon admission of air is the pool of 2-octaprenyl phenol converted to ubiquinone-8. This reaction occurs in the cytoplasmic membrane and is significantly inhibited by cytochrome P-450 inhibitors. The rate for 2-octaprenyl phenol conversion is strongly dependent on temperature. The Arrhenius plot shows inflection points at 32 degrees C and 16 degrees C. Enzymes for ubiquinone-8 synthesis are absent from anaerobically grown E. coli. Processing of 4-hydroxy[U-14C]benzoate by these cells starts only when protein synthesis is permitted under aerobic conditions.

MeSH terms

  • Cytochrome P-450 Enzyme System / metabolism
  • Escherichia coli / metabolism*
  • Hydroxybenzoates / metabolism
  • Kinetics
  • Mutation
  • Oxygen / pharmacology*
  • Species Specificity
  • Temperature
  • Terpenes
  • Ubiquinone / biosynthesis*


  • Hydroxybenzoates
  • Terpenes
  • Ubiquinone
  • 2-octaprenyl phenol
  • Cytochrome P-450 Enzyme System
  • Oxygen