PT  - JOURNAL ARTICLE
AU  - Britta Bonn
AU  - Collen M. Masimirembwa
AU  - Yasmin Aristei
AU  - Ismael Zamora
TI  - The Molecular Basis of CYP2D6-Mediated <em>N</em>-Dealkylation: Balance between Metabolic Clearance Routes and Enzyme Inhibition
AID  - 10.1124/dmd.108.022376
DP  - 2008 Nov 01
TA  - Drug Metabolism and Disposition
PG  - 2199--2210
VI  - 36
IP  - 11
4099  - http://dmd.aspetjournals.org/content/36/11/2199.short
4100  - http://dmd.aspetjournals.org/content/36/11/2199.full
SO  - Drug Metab Dispos2008 Nov 01; 36
AB  - N-Dealkylation is a commonly observed metabolic reaction for drugs containing secondary and tertiary amines. On searching the literature, it is obvious that this reaction is far less common among cytochrome P450 2D6 catalyzed reactions compared with other cytochromes P450. The CYP2D6 pharmacophore and characteristic features in the active site cavity suggest a favored substrate orientation that prevents N-dealkylation from occurring. In this study, the literature was searched for N-dealkylated and non-N-dealkylated CYP2D6 substrates. The hypothesis that was suggested and confirmed demonstrated that N-dealkylation occurs by this enzyme when the preferred site of metabolism is blocked toward other oxidative metabolic pathways. An interesting observation was also that addition of stable groups at preferred sites of metabolism generally improved the metabolic stability but also resulted in retained or increased inhibition of the enzyme. In addition, the effect of pH on N- and O-dealkylation of dextromethorphan was shown to be consistent with the hypothesis that an ionized amino function favored substrate dockings resulting in O-dealkylation. The American Society for Pharmacology and Experimental Therapeutics