Detoxication cytochrome P450 enzymes

Comparative biochemistry. Some researchers believe that the proper role of comparative biochemistry is to put evolution on a molecular basis, and that detoxication enzymes, like other enzymes, are suitable subjects for study. Xenobiotic-metabolizing enzymes were probably essential in the early stages of animal evolution because secondary plant products, even those of low toxicity, are frequently lipophilic and as a consequence would, in the absence of such enzymes, accumulate in lipid membranes and lipid depots. The evolution of cytochrome P450 isoforms, with more than 2000 isoform cDNA sequences known, is proving a useful tool for the study of biochemical evolution. 

Monooxvgenases. These enzymes are important in the detoxication of pyrethroid, carbamate, organophosphorus and other classes of insecticides (2). They are microsomal, membrane associated enzymes which catalyze reactions in which one atom from molecular oxygen is inserted into the insecticide and the second oxygen atom is reduced to form water. Catalysis depends on the close association of the heme-containing cytochrome P450 terminal oxidase with NADPH cytochrome C reductase for electron transport, and it also depends on availability of NADPH and oxygen. 

Debersac, P. et al. Induction of cytochrome P450 and/or detoxication enzymes by various extracts of rosemary description of specific patterns. Food Chem. Toxicol, 39, 907,2001. 

The cytochrome P450 (GYP) family of enzymes are the major catalysts that are responsible for a variety of oxidation reactions associated with the biotransformation of many xenobiotics that can be used to illustrate several concepts of toxication and detoxication in a chemistry course. The main function of this group of isozymes is to insert one atom of oxygen into a substrate thereby increasing hydrophilicity or water solubility. These enzymes are haem-containing proteins containing a reduced iron species essential for transferring electrons and work in concert with coenzymes NADPH and NADPH reductase. 

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