Heterologous Expression and Functional Characterization of Cytochrome P450 1A1 from Common Minke Whale(Balaenoptera acutorostrata)

摘要

While marine mammals accumulate organochlorine contaminants such as PCDDs(polychlorinated dibenzo-p-dioxins),PCDFs(polychlorinated dibenzofurans),PCBs(polychlorinated biphenyls)and DDTs(1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane and its metabolites)to a great extent,little is known about the metabolic potential of these chemicals in marine mammals.A large number of studies have shown that cytochrome P450(CYP),a drug-metabolizing enzyme,participates in the metabolism of such organochlorine contaminants in rodents and human.To understand metabolic potential of cetacean CYPs,we initially isolated CYP1A1 cDNA from a hepatic cDNA library of common minke whale {Balaenoptera acutorostrata).Minke whale CYP1A1 protein was heterologously expressed in yeast cell.The expression of recombinant minke whale CYP1A1 protein was confirmed from the reduced CO-difference spectrum.Minke whale CYP1A1 showed the highest activity of ethoxyresorufin-O-deethylase(EROD),followed by methoxyresorufin-O-demethylase(MROD).Activities of pentoxyresorufin-O-depenthylase(PROD)and benzoyloxgamma-resorufin-O-debenzylase(BROD)by minke whale CYP1A1 were relatively low.This study will be a first step toward the understanding of species-and isoform-specific metabolism of environmental contaminants,and their underlying molecular mechanisms.