Reduction of tertiary amine N-oxides by liver preparations: function of aldehyde oxidase as a major N-oxide reductase

Biochem Biophys Res Commun. 1984 Jun 29;121(3):749-54. doi: 10.1016/0006-291x(84)90742-3.


Reduction of tertiary amine N-oxides to the corresponding amines by liver preparations was investigated with imipramine N-oxide and cyclobenzaprine N-oxide under anaerobic conditions. Rabbit liver cytosol in the presence of an electron donor of aldehyde oxidase exhibited a significant N-oxide reductase activity which is comparable to the activity of the liver microsomes supplemented with NADPH. Rabbit liver aldehyde oxidase also exhibited the N-oxide reductase activity in the presence of its electron donor, indicating that the activity observed in the liver cytosol is due to this cytosolic enzyme. Furthermore, the tertiary amine N-oxide reductase activity of liver cytosols from rats, mice, hamsters and hogs was demonstrated by comparison with that of liver microsomes from these mammalian species.

Publication types

  • Comparative Study

MeSH terms

  • Aldehyde Oxidase
  • Aldehyde Oxidoreductases / metabolism*
  • Amines / metabolism*
  • Amitriptyline / analogs & derivatives
  • Amitriptyline / metabolism
  • Animals
  • Cricetinae
  • Cytochrome P-450 Enzyme System / metabolism
  • Cytosol / enzymology
  • Dibenzocycloheptenes*
  • Imipramine / analogs & derivatives
  • Imipramine / metabolism
  • Liver / enzymology*
  • Mice
  • Microsomes, Liver / enzymology
  • Oxidation-Reduction
  • Rabbits
  • Rats
  • Species Specificity
  • Substrate Specificity
  • Swine


  • Amines
  • Dibenzocycloheptenes
  • Amitriptyline
  • N,N-dimethyl-5H-dibenzo(a,d)cycloheptene-delta 5,alpha-propylamine N-oxide
  • imipramine N-oxide
  • Cytochrome P-450 Enzyme System
  • Aldehyde Oxidoreductases
  • Aldehyde Oxidase
  • Imipramine