In vitro enantioselective biotransformation of chiral polychlorinated biphenyls

ENVR 69

Nicholas A. Warner1, Jonathan W. Martin2, and Charles S. Wong1. (1) Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, AB T6G 2G2, Canada, (2) Department of Public Health Sciences, University of Alberta, 11350 83 Avenue, Edmonton, AB T6G 2G3, Canada
In vitro experiments were conducted to understand the stereoselectivity of mammalian polychlorinated biphenyls' (PCBs) biotransformation reactions. Chiral compounds exist as two stereoisomers that have the same chemical/physical properties, but may differ in their biological and toxicological properties, making enantioselective analysis an useful tool in accessing biochemical weathering of chiral pollutants within the environment. Non-racemic proportions of chiral PCBs have been reported in organisms from various ecosystems. Although this enantiomeric enrichment has been attributed to biotransformation, the mechanism in which this occurs is poorly understood. To understand this mechanism better, rat and human cytochrome P450 (CYP) enzymes were incubated with several chiral PCBs (PCB 45, 84, 91, 95, 132, 136, 149 and 183) to investigate enantioselective metabolism. Enantioselective metabolism was observed within 30 minutes for several of the targeted congeners when incubated with rat CYP 2B1 and human CYP 2B6. Evidence for the formation of hydroxylated metabolites was also found for several of the chiral congeners and shows that enantioselective metabolism is occurring for Phase I PCB toxicokinetics.
 

Symposium Honoring Dr. Walter Giger
8:30 AM-12:40 PM, Tuesday, August 21, 2007 Boston Park Plaza -- Stanbro Rm, Oral

Division of Environmental Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007