Expression, purification, and characterization of mouse CYP2D22

Aiming Yu, Robert L. Haining

Research output: Contribution to journalArticle

23 Scopus citations

Abstract

Metabolism of the prototype human CYP2D6 substrates debrisoquine and bufuralol proceeds at a much slower rate in mice; therefore, the mouse has been proposed as an animal model for the human CYP2D6 genetic deficiency. To interpret the molecular mechanism of this deficiency, a cDNA belonging to the CYP2D gene subfamily (Cyp2d22) has been cloned and sequenced from a mouse mammary tumor-derived cell line. In the current study, Cyp2d22 enzyme was overexpressed and purified from insect cells using a baculovirus-mediated system. The activity of this purified enzyme was directly compared with purified human CYP2D6 toward codeine, dextromethorphan, and methadone as substrates. Purified Cyp2d22 was found to catalyze the O-demethylation of dextromethorphan with significantly higher Km values (250 μM) than that (4.2 μM) exhibited by purified human CYP2D6. The Km for dextromethorphan N-demethylation by Cyp2d22 was found to be 418 μM, much lower than that observed with human CYP2D6 and near the Km for dextromethorphan N-demethylation catalyzed by CYP3A4. CYP2D6 catalyzed codeine O-demethylation, whereas Cyp2d22 and CYP3A4 mediated codeine N-demethylation. Furthermore, methadone, a known CYP3A4 substrate and CYP2D6 inhibitor, was N-demethylated by Cyp2d22 with a Km of 517 μM and Vmax of 4.9 pmol/pmol/min. Quinidine and ketoconazole, potent inhibitors to CYP2D6 and CYP3A4, respectively, did not show strong inhibition toward Cyp2d22-mediated dextromethorphan O-or N-demethylation. These results suggest that mouse Cyp2d22 has its own substrate specificity beyond CYP2D6-like-deficient activity.

Original languageEnglish (US)
Pages (from-to)1167-1174
Number of pages8
JournalDrug Metabolism and Disposition
Volume34
Issue number7
DOIs
StatePublished - 2006
Externally publishedYes

ASJC Scopus subject areas

  • Pharmacology
  • Toxicology

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