Microsomal cytochrome monooxygenases

Williams PA, Cosme J, Sridhar V, Johnson EF, McRee DE. Mammalian microsomal cytochrome P450 monooxygenase structural adaptations for membrane binding and functional diversity. Mol Cell 2000 5 121-31. 

Shimada, T. and Y. Sawabe. 1983. Activation of 3,4,3, 4 -tetrachlorobiphenyl to protein-based metabolites by rat liver microsomal cytochrome P-448 containing monooxygenase system. Toxicol. Appl. Pharmacol. 70 486-493. 

Gorsky LD, Koop DR, Coon MJ. On the stoichiometry of the oxidase and monooxygenase reactions catalyzed by liver microsomal cytochrome P-450. Products of oxygen reduction. J Biol Chem 1984 259(11) 6812-6817. 

Karuzina, I.I. and Archakov, A.I. (1994) Hydrogen peroxide-mediated inactivation of microsomal cytochrome P450 during monooxygenase reactions. Free Radical Biology and Medicine, 17 (6), 557-567. 

Robacker KM, Kulkarni AP, Hodgson E. 1981. Pesticide induced changes in the mouse hepatic microsomal cytochrome P-450-dependant monooxygenase system and other enzymes. J Environ Sci Health (Part B Pestic Food Contam Agric Wastes) 16(5) 529-546. 

Orrenius, S. and Ernster, L. Microsomal cytochrome P-l+50-linked monooxygenase systems in mammalian tissues. In Hayaishi, 0. (Ed.) Molecular Mechanisms of Oxygen Activation (197 0 Academic Press, New York, pp 215-21+1+. 

Minn AT, Pelczar H, Denizot C, Martinet M, Heydel JM, et al. 2005. Characterization of microsomal cytochrome P450-dependent monooxygenases in the rat olfactory mucosa. Drug Metab Dispos 33 1229-1237. 

Specific isozymes of microsomal cytochrome P450 monooxygenases convert AA to hydroxy- or epoxyeicosatrienoic acids (Figures... 

One important finding from purification studies as well as cloning and expressing of individual isoforms is that the lack of substrate specificity of microsomes for monooxygenase activity is not an artifact caused by the presence of several specific cytochromes. Rather, it appears that many of the cytochromes isolated are still relatively nonspecific. The relative activity toward different substrates does nevertheless vary greatly from one CYP isoform to another even when both are relatively nonspecific. This lack of specificity is illustrated in Table 7.2, using human isoforms as examples. 

Spironolactone exhibits antiandrogenic effects in males and females. It decreases testosterone biosynthesis by inhibiting steroid 17a-monooxygenase (17a-hydroxylase) activity, possibly secondary to destruction of microsomal cytochrome P-450 in tissues with high steroid 17a-monooxygenase activity (testes, adrenals) [65],... 

Salaun, J.P., Benveniste, I., Reichhart, D., and Durst, F., A microsomal (cytochrome P-450)-linked lauric-acid-monooxygenase from aged Jerusalem artichoke tuber tissues, Eur. J. Biochem., 90, 155-159, 1978. 

A feature of some pterocarpan phytoalexins (e.g., pisatin and glyceollin of pea and soybean, respectively) is their hydroxylation at position 6a, a reaction catalyzed by a microsomal cytochrome P450 monooxygenase.49 50 A cDNA encoding this enzyme was recently characterized from elicited soybean cell cultures.51 The microsomal protein, expressed in yeast cells, catalyzed the stereoselective hydroxylation of (6a/ , lla/ )-3,9-dihydroxypterocarpan to its 6a-hydroxy derivative. It was also demonstrated that the enzyme expression is regulated at the transcriptional level.51... 

In animal models, activation of AFB, by microsomal cytochrome P-450 is required for carcinogenicity [72, 76]. One of the cytochrome P-450 monooxygenases in the liver converts AFB, to a variety of metabolites of increased... 

Cytochrome P450 reductase is the physiological reductant of a wide range of microsomal cytochrome P450 monooxygenase isozymes that... 

---