Unusual regioselectivity and active site topology of human cytochrome P450 2J2

Biochemistry. 2007 Sep 11;46(36):10237-47. doi: 10.1021/bi700876a. Epub 2007 Aug 17.


The oxidation of six derivatives of terfenadone by recombinant human CYP2J2 (CYP = cytochrome P450) was studied by high-performance liquid chromatography coupled to mass spectrometry (MS) using tandem MS techniques and by 1H NMR spectroscopy. CYP2J2 exhibited a surprising regioselectivity in favor of the hydroxylation of the substrate terminal chain at the weakly reactive homobenzylic position. In contrast, hydroxylation of the same substrates by CYP3A4 mainly occurred on the most chemically reactive sites of the substrates (N-oxidation and benzylic hydroxylation). A 3D homology model of CYP2J2 was constructed using recently published structures of CYP2A6, CYP2B4, CYP2C8, CYP2C9, and CYP2D6 as templates. In contrast with other CYP2 structures, it revealed an active site cavity with a severely restricted access of substrates to the heme through a narrow hydrophobic channel. Dynamic docking of terfenadone derivatives in the CYP2J2 active site allowed one to interpret the unexpected regioselectivity of the hydroxylation of these substrates by CYP2J2, which is mainly based on this restricted access to the iron. The structural features that have been found to be important for recognition of substrates or inhibitors by CYP2J2 were also interpreted on the basis of CYP2J2-substrate interactions in this model.

Publication types

  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Binding Sites
  • Carbon
  • Catalysis
  • Cytochrome P-450 CYP2J2
  • Cytochrome P-450 CYP3A
  • Cytochrome P-450 Enzyme System / chemistry*
  • Cytochrome P-450 Enzyme System / metabolism*
  • Histamine H1 Antagonists / chemistry
  • Histamine H1 Antagonists / metabolism
  • Humans
  • Hydroxylation
  • Insecta
  • Iron
  • Ketones / chemistry
  • Kinetics
  • Mass Spectrometry
  • Models, Molecular
  • Oxidation-Reduction
  • Oxygenases / chemistry*
  • Oxygenases / metabolism*
  • Structural Homology, Protein
  • Substrate Specificity


  • CYP2J2 protein, human
  • Histamine H1 Antagonists
  • Ketones
  • Carbon
  • Cytochrome P-450 Enzyme System
  • Iron
  • Oxygenases
  • Cytochrome P-450 CYP2J2
  • Cytochrome P-450 CYP3A
  • CYP3A4 protein, human