Cytochrome P-450 and FAD-monooxygenase mediated S- and N-oxygenations

S- and N-Oxygenations are mostly mediated by either the cytochrome P-450 group of enzymes (haemoproteins), or the FAD-containing monooxygenases (flavoproteins). The nucleophilicity of the heteroatom may be an important determinant of which of these microsomal enzymes is utilised for specific oxygenations. This article describes the approaches that could be used for assessing the relative contribution of these microsomal oxidases to a particular reaction, with reference to studies with N,N-dimethylaniline, diethylsulphide, tetrahydrothiophen and dibenzothiophen.