The tissue- and species-selective toxicity of a number of pulmonary toxicants has been attributed to the presence and distribution of activating enzymes with high kcat in target airways of susceptible species. The mouse is especially sensitive to a variety of metabolically activated lung toxicants. Recombinant CYP2F2 (mouse) was recently shown to effectively metabolize the species-selective pulmonary toxicant naphthalene. Here we show that the pulmonary toxicants 1-nitronaphthalene and 2-methylnaphthalene are metabolized readily with high kcat values (17.1 and 67.6 min-1, respectively) to potentially cytotoxic intermediates at biologically relevant Km values (21.5 and 3.7 μM, respectively). Additionally, anthracene and benzo[a]pyrene are both metabolized by CYP2F2 (0.14 ± 0.04 and 0.04 ± 0.00 nmol/nmol/min, respectively), albeit at much lower rates. The levels of total CYP in mouse airways are considerably higher than those in parenchyma and trachea, and this is consistent with much higher rates of naphthalene metabolism in microsomal preparations from airways compared with the other subcompartments. The data suggest that CYP2F2 is a prominent cytochrome P450 in mouse lung that metabolizes a number of pulmonary toxicants. The presence of CYP2F2 may be important in the susceptibility of the mouse to metabolically activated pulmonary toxicants.
|Original language||English (US)|
|Number of pages||10|
|Journal||Journal of Pharmacology and Experimental Therapeutics|
|State||Published - 2001|
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