TY - JOUR
T1 - Equine cytochrome P450 2C92
T2 - cDNA cloning, expression and initial characterization
AU - DiMaio Knych, H. K.
AU - DeStefano Shields, C.
AU - Buckpitt, A. R.
AU - Stanley, S. D.
PY - 2009/5/1
Y1 - 2009/5/1
N2 - Substantial gaps exist in our knowledge of the metabolic clearance of therapeutic agents in horses. Accordingly, a cytochrome P450 monooxygenase in the 2C family was cloned from an equine liver, sequenced and expressed in a baculovirus expression system. Catalytic activities of the recombinant protein were measured with a number of substrates. The protein, assigned CYP2C92, displayed optimal catalytic activity with diclofenac using molar ratios of CYP2C92 to NADPH CYP450 reductase of 1:18. Addition of cytochrome b5 to diclofenac incubations had no significant effect on metabolic turnover. CYP2C92 catalyzed diclofenac metabolism was 20-fold slower than the human counterpart, CYP2C9. CYP2C92 demonstrated comparable tolbutamide and (S)-warfarin hydroxylase activity compared to CYP2C9, upon addition of b5 to the reactions. The results of this study demonstrate substantial interspecies differences in metabolism of substrates by CYP2C orthologues in the horse and human and support the need to fully characterize this enzyme system in equids.
AB - Substantial gaps exist in our knowledge of the metabolic clearance of therapeutic agents in horses. Accordingly, a cytochrome P450 monooxygenase in the 2C family was cloned from an equine liver, sequenced and expressed in a baculovirus expression system. Catalytic activities of the recombinant protein were measured with a number of substrates. The protein, assigned CYP2C92, displayed optimal catalytic activity with diclofenac using molar ratios of CYP2C92 to NADPH CYP450 reductase of 1:18. Addition of cytochrome b5 to diclofenac incubations had no significant effect on metabolic turnover. CYP2C92 catalyzed diclofenac metabolism was 20-fold slower than the human counterpart, CYP2C9. CYP2C92 demonstrated comparable tolbutamide and (S)-warfarin hydroxylase activity compared to CYP2C9, upon addition of b5 to the reactions. The results of this study demonstrate substantial interspecies differences in metabolism of substrates by CYP2C orthologues in the horse and human and support the need to fully characterize this enzyme system in equids.
KW - CYP2C
KW - CYP450
KW - Diclofenac
KW - Horse
KW - Mephenytoin
KW - Phase I metabolism
KW - Tolbutamide
KW - Warfarin
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U2 - 10.1016/j.abb.2009.02.009
DO - 10.1016/j.abb.2009.02.009
M3 - Article
C2 - 19245785
AN - SCOPUS:64549119690
SN - 0003-9861
VL - 485
SP - 49
EP - 55
JO - Archives of Biochemistry and Biophysics
JF - Archives of Biochemistry and Biophysics
IS - 1
ER -