Identification and functional characterization of novel feline cytochrome P450 2A.

Cytochrome P450s are the major metabolizing enzymes for xenobiotics in humans and other mammals. Although the domestic cat Felis catus, an obligate carnivore, is the most common companion animal, the properties of cytochrome P450 subfamilies are largely unknown. We newly identified the feline CYP2A13, which consists of 494 deduced amino acids, showing the highest identity to CYP2As of dogs, followed by those of pigs, cattle and humans. The feline CYP2A13 transcript and protein were expressed almost exclusively in the liver without particular sex-dependent differences. The feline CYP2A13 protein heterogeneously expressed in Escherichia coli showed metabolic activity similar to those of human and canine CYP2As for coumarin, 7-ethoxycoumarin and nicotine. 5. The results indicate the importance of CYP2A13 in systemic metabolism of xenobiotics in cats.