Polysubstrate monooxygenases in Drosophila, mammals and man

There is overwhelming evidence that polysubstrate monooxygenases play a central role in the metabolism of endogenous compounds as well as in the biotransformation of xenobiotics. These enzyme systems are of great importance in such diverse fields as insecticide resistance, mutagenicity, carcinogenicity, drug metabolism, etc. The constitutive and, in particular, the induced forms represent various products from a multigene family. This has first been shown for the mouse, but evidence is accumulating that this is also true for other mammals and for man. Also in insects a similar picture is emerging. If the regulation of cytochrome P-450 induction resembles in any way the other methods by which prokaryotes and eukaryotes cope genetically with the many forms of environmental selective pressures, it is very likely that most organisms have the genetic capacity to produce not only hundreds but probably thousands of inducible forms of cytochrome P-450 (Nebert et al., 1981). Doubtless, many fields from pest control to cancer prevention to drug safety will profit from the elucidation of the genetic mechanisms involved.