Cloning of a cDNA encoding a novel marmoset CYP2C enzyme, expression in yeast cells and characterization of its enzymatic functions

Biochem Pharmacol. 2006 Dec 15;72(12):1738-48. doi: 10.1016/j.bcp.2006.08.025. Epub 2006 Sep 29.


We cloned a cDNA encoding a novel CYP2C enzyme, called P450 M-2C, from a marmoset liver. The deduced amino acid sequence showed high identities to those of human CYP2C8 (87%), CYP2C9 (78%) and CYP2C19 (77%). The P450 M-2C enzyme expressed in yeast cells catalyzed p-methylhydroxylation of only tolbutamide among four substrates tested, paclitaxel as a CYP2C8 substrate, diclofenac and tolbutamide as CYP2C9 substrates and S-mephenytoin as a CYP2C19 substrate. p-Methylhydroxylation of tolbutamide by marmoset liver microsomes showed monophasic kinetics, and the apparent K(m) value (1.2 mM) for the substrate was similar to that of the recombinant P450 M-2C (1.8 mM). Although all of the recombinant human CYP2C8, CYP2C9 and CYP2C19 expressed in yeast cells catalyzed tolbutamide p-methylhydroxylation, the kinetic profile of CYP2C8 was most similar to that of P450 M-2C. Tolbutamide oxidation by the marmoset liver microsomes and the recombinant P450 M-2C was inhibited most effectively by quercetin, a CYP2C8 inhibitor, followed by omeprazole, a CYP2C19 inhibitor, whereas sulfaphenazole, a CYP2C9 inhibitor, was less potent under the conditions used. These results indicate that P450 M-2C is the major tolbutamide p-methylhydroxylase in the marmoset liver.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Binding Sites
  • Blotting, Western
  • Callithrix
  • Cloning, Molecular
  • Cytochrome P-450 Enzyme Inhibitors
  • Cytochrome P-450 Enzyme System / genetics*
  • Cytochrome P-450 Enzyme System / metabolism*
  • DNA, Complementary / genetics*
  • Enzyme Inhibitors / pharmacology
  • Female
  • Humans
  • Hydroxylation
  • Microsomes, Liver / enzymology*
  • Models, Molecular
  • Molecular Sequence Data
  • Saccharomyces cerevisiae / genetics*
  • Sequence Alignment
  • Substrate Specificity


  • Cytochrome P-450 Enzyme Inhibitors
  • DNA, Complementary
  • Enzyme Inhibitors
  • cytochrome P-450 CYP2C subfamily
  • Cytochrome P-450 Enzyme System