Microsomes mixed function amine oxidase

Prough RA. 1973. The N-oxidation of alkylhydrazines catalyzed by the microsomal mixed-function amine oxidase. Arch Biochem Biophys 158 442-444. 

ESR investigations of microsomal drug oxidation have been reported. For example, the microsomal enzyme mixed function amine oxidase converts hindered hydroxyl-amines to the corresponding ESR-detectable nitroxides. From a comparison of rates of nitroxide and superoxide production, it has been concluded [177] that oxidation of the hydroxylamine is mediated solely by enzyme-generated superoxide radical. In addition, it appears that some oxidations mediated by cytochrome P-450 may occur, at least in part, by a one-electron mechanism. Oxidation of several dihydropyridine derivatives and some substituted hydrazines in the presence of spin traps has given spectra of spin-adducts consistent with radical production from the P-450 substrates [178]. Cumene hydroperoxide has been shown to support the P-450-catalyzed oxidation of aminopyrine to its radical cation [179]. 

Ziegler DM, Mitchell CH. Microsomal oxidase IV properties of a mixed-function amine oxidase isolated from pig liver microsomes. Arch Biochem Biophys 1972 150 116-125. 

For foreign compounds, the majority of oxidation reactions are catalyzed by monooxygenase enzymes, which are part of the mixed function oxidase (MFO) system and are found in the SER (and also known as microsomal enzymes). Other enzymes involved in the oxidation of xenobiotics are found in other organelles such as the mitochondria and the cytosol. Thus, amine oxidases located in the mitochondria, xanthine oxidase, alcohol dehydrogenase in the cytosol, the prostaglandin synthetase system, and various other peroxidases may all be involved in the oxidation of foreign compounds. 

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