Structure, Function, and Genetic Variation of CYP2D6, a Cytochrome Metabolizing Drugs

Cytochromes P450 (CYPs) are a large family of heme-containing monooxygenase enzymes involved in the metabolism of organic compounds. They take part in both the synthesis of endogenous compounds and the disposal of xenobiotics, being particularly involved in drug metabolism. Among the members of the family, the 2D6 isoform is the most extensively investigated one. Having a highly polymorphic nature, with remarkable inter-individual and inter-ethnic differences, its activity may differ significantly from individual to individual. As it is responsible for metabolizing many clinically relevant therapeutic compounds, its features make it difficult to strike a balance between the therapeutic and the toxic effects of drugs being taken. This chapter deals with the CYP superfamily, focusing on CYP2D6. Special emphasis has been given to the genetic polymorphism of the enzyme to provide the readers with a clear picture of its importance in the management of drug administration.