The catalytic efficiences of cytochrome P450 (P450)-mediated N-oxidation of the 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) by recombinant human P450 1A2 were 10-19-fold higher than rat P450 1A2, while methoxyresorufin O-demethylation activity was comparable for both P450s. Similar findings were observed with rat and human liver microsomal samples. Interspecies differences in P450 enzyme expression and catalytic activities may be significant and must be considered when assessing human health risk. Copyright (C) 1999 Elsevier Science Ireland Ltd.
Bibliographical noteFunding Information:
This work was supported in part by United States Public Health Service Grant R35 CA44353 and P30 ESOO267
- Cytochrome P450
- Food carcinogens
- Hetercyclic aromatic amines (HAAs)
- Interspecies comparisons