Peroxidase-catalyzed in vitro formation of polychlorinated dibenzo-p-dioxins and dibenzofurans from chlorophenols.
Chlorophenols (CP) are transformed in vitro to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) by a peroxidase-catalyzed oxidation. This is shown for 2,4,5-tri-, 2,3,4,6-tetra- and pentachlorophenol with plant horseradish peroxidase and with myeloperoxidase recovered from human leukocytes, each in the presence of hydrogen peroxide. The yield, the reaction and the PCDD/F-pattern found are dependent on the CP. The amounts of PCDD/F formed within 4 or 24 h are in the micromol/mol-range for all substrates and both peroxidases. The experiments suggest that biochemical formation of PCDD/F from precursors such as CPs can take place in the human body and that this metabolic pathway may lead to a higher inner exposure to PCDD/F than up to now assumed based on intake data for PCDD/F.
Wittsiepe
J
J
Ruhr-Universität Bochum, Abteilung für Hygiene, Sozial- und Umweltmedizin, Germany. wittsiepe@hygiene.ruhr-uni-bochum.de
Kullmann
Y
Y
Schrey
P
P
Selenka
F
F
Wilhelm
M
M
D001572:Benzofurans / Q000378:metabolism*; D001711:Biotransformation; D002733:Chlorophenols / Q000378:metabolism*; D000072338:Dibenzofurans, Polychlorinated; D006735:Horseradish Peroxidase / Q000502:physiology*; D006801:Humans; D009195:Peroxidase / Q000502:physiology*; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000378:metabolism
D001572:Benzofurans; D002733:Chlorophenols; D000072338:Dibenzofurans, Polychlorinated; D000072317:Polychlorinated Dibenzodioxins; D006735:Horseradish Peroxidase; D009195:Peroxidase