Involvement of mixed function oxidase systems in polychlorinated biphenyl metabolism by plant cells.

Nineteen different polychlorinated biphenyl (PCB) congeners ranging in chlorine content from 2 to 6 chlorine atoms were provided to nonphotosynthetic suspension cultures of rose (Rosa sp. cv. Paul's Scarlet). After a 96 h incubation period, 11 individual congeners had been metabolized by > 10%. Provision of mixed function oxidase inhibitors (10 mM metyrapone or 0.5 mM 7,8-benzoflavone) either stopped or severely reduced the metabolism of individual congeners; whereas (inhibitors of peroxidase) (1 mM benzoate or 1 mM n-propylgallate) had minimal influence on PCB metabolism. The metabolism of PCBs by rose cultures appears to be catalyzed by a cytochrome P-450-and/or P-448-dependent enzyme system.