Function of Metabolism Biotransformation

Cytochrome P450 monooxygenase Azo and nitro group reductase Aldehyde dehydrogenase 

The cytochrome P450 system can carry out a variety of oxidation reactions as listed in Table 7.2. 

The overall scheme for these reactions is the insertion of a single oxygen atom into the drug molecule. Current views indicate that the chemistry of cytochrome P450 is radical by nature. 

The mechanism of cytochrome P450 catalysis is probably constant across the system. It is determined by the ability of a high valent formal (FeO) species to carry out one-electron oxidations through the abstraction of hydrogen atoms or electrons. The resultant substrate radical can then recombine with the newly created hydroxyl radical (oxygen rebound) to form the oxidized metabolite. Where a heteroatom is the (rich) source of the electron more than one product is possible. There can be direct recombination to yield the heteroatom oxide or radical relocalization within the 

Alcohol oxidation Alcohol to carboxylic acid Losartan 

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