title: Reduction of tertiary amine N-oxides by liver preparations: function of aldehyde oxidase as a major N-oxide reductase.
abstract: 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.
mesh_terms: D042931:Aldehyde Oxidase; D000445:Aldehyde Oxidoreductases / Q000378:metabolism*; D000588:Amines / Q000378:metabolism*; D000639:Amitriptyline / Q000031:analogs & derivatives / Q000378:metabolism; D000818:Animals; D006224:Cricetinae; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D003600:Cytosol / Q000201:enzymology; D003986:Dibenzocycloheptenes; D007099:Imipramine / Q000031:analogs & derivatives / Q000378:metabolism; D008099:Liver / Q000201:enzymology*; D051379:Mice; D008862:Microsomes, Liver / Q000201:enzymology; D010084:Oxidation-Reduction; D011817:Rabbits; D051381:Rats; D013045:Species Specificity; D013379:Substrate Specificity; D013552:Swine
chemical_list: D000588:Amines; D003986:Dibenzocycloheptenes; D000639:Amitriptyline; C010930:N,N-dimethyl-5H-dibenzo(a,d)cycloheptene-delta 5,alpha-propylamine N-oxide; C002921:imipramine N-oxide; D003577:Cytochrome P-450 Enzyme System; D000445:Aldehyde Oxidoreductases; D042931:Aldehyde Oxidase; D007099:Imipramine