Biomaterial Database

Metabolism of (14)C-labeled polychlorinated biphenyl congeners by wheat cell suspension cultures. 2015

Nicola Classen, and Xin Lin, and Burkhard Schmidt

a Institute of Biology V , RWTH Aachen University , Aachen , Germany.

The metabolism of [UL-(14)C]-2,2',5,5'-tetrachlorobiphenyl ((14)C-PCB-52), [UL-(14)C]-2,2',4,4',5,5'-hexachlorobiphenyl ((14)C-PCB-153, and a congeneric mixture of [UL-(14)C]-labeled polychlorinated biphenyls ((14)C-PCB-Mix) was studied in cell suspension cultures of wheat (Triticum aestivum L. cv. 'Heines Koga II'). About 50% of applied (14)C-PCB-52 (20 μg/assay) was transformed during 96 h of incubation. While 7.6% on non-extractable residues emerged, turnover of (14)C-PCB-52 was mainly due to soluble polar metabolites. These were subjected to chemical glycoside cleavage. In the resulting hydrolysate, four aglycons were identified by GC-EIMS, namely four tetrachloro-hydroxy-biphenyl isomers (C6H6Cl4O, M(+·) at m/z = 306, 308, 310 and 312), and one trichloro-hydroxy-biphenyl (C6H7Cl3O, M(+·) at m/z = 272, 274 and 276). Number and character of hydroxylated products pointed to cytochromes P450 as enzymatic catalysts of hydroxylation. (14)C-PCB-153 was metabolized by wheat to minor degree if at all. Due to GC-EIMS analysis, of (14)C-PCB-Mix consisted of biphenyl, one mono-, four di-, seven tri-, eleven tetra-, and four pentachlorobiphenyls besides traces of further mono- and hexachlorobiphenyls. Among these were PCB-28, PCB-52, PCB 101, and PCB-118 (identified by seven key congeners standard). The mixture resembled industrial products Clophen A30 or Aroclor 1016. Metabolic turnover of applied (14)C-PCB-Mix (15 μg/assay) was 30% after 96 h; 8.4% of non-extractable residues emerged. Using DDE (p,p'-dichlorodiphenyl-dichloroethylene) as internal standard it was demonstrated that biphenyl, one monochloro-, two dichloro-, and one trichlorobiphenyl were completely metabolized to polar products. Partial metabolization occurred with one di-, five tri-, and four tetrachlorobiphenyls. Two tri-, four tetra-, and all pentachlorbiphenyls proved to be stable. Due to strong interference by matrix, evaluation of three congeners was not possible. In addition to wheat, results of similar experiments with cell cultures of other species are briefly mentioned.

UI	MeSH Term	Description	Entries
D011078	Polychlorinated Biphenyls	Industrial products consisting of a mixture of chlorinated biphenyl congeners and isomers. These compounds are highly lipophilic and tend to accumulate in fat stores of animals. Many of these compounds are considered toxic and potential environmental pollutants.	PCBs,Polychlorinated Biphenyl,Polychlorobiphenyl Compounds,Biphenyl, Polychlorinated,Biphenyls, Polychlorinated,Compounds, Polychlorobiphenyl
D002250	Carbon Radioisotopes	Unstable isotopes of carbon that decay or disintegrate emitting radiation. C atoms with atomic weights 10, 11, and 14-16 are radioactive carbon isotopes.	Radioisotopes, Carbon
D003577	Cytochrome P-450 Enzyme System	A superfamily of hundreds of closely related HEMEPROTEINS found throughout the phylogenetic spectrum, from animals, plants, fungi, to bacteria. They include numerous complex monooxygenases (MIXED FUNCTION OXYGENASES). In animals, these P-450 enzymes serve two major functions: (1) biosynthesis of steroids, fatty acids, and bile acids; (2) metabolism of endogenous and a wide variety of exogenous substrates, such as toxins and drugs (BIOTRANSFORMATION). They are classified, according to their sequence similarities rather than functions, into CYP gene families (>40% homology) and subfamilies (>59% homology). For example, enzymes from the CYP1, CYP2, and CYP3 gene families are responsible for most drug metabolism.	Cytochrome P-450,Cytochrome P-450 Enzyme,Cytochrome P-450-Dependent Monooxygenase,P-450 Enzyme,P450 Enzyme,CYP450 Family,CYP450 Superfamily,Cytochrome P-450 Enzymes,Cytochrome P-450 Families,Cytochrome P-450 Monooxygenase,Cytochrome P-450 Oxygenase,Cytochrome P-450 Superfamily,Cytochrome P450,Cytochrome P450 Superfamily,Cytochrome p450 Families,P-450 Enzymes,P450 Enzymes,Cytochrome P 450,Cytochrome P 450 Dependent Monooxygenase,Cytochrome P 450 Enzyme,Cytochrome P 450 Enzyme System,Cytochrome P 450 Enzymes,Cytochrome P 450 Families,Cytochrome P 450 Monooxygenase,Cytochrome P 450 Oxygenase,Cytochrome P 450 Superfamily,Enzyme, Cytochrome P-450,Enzyme, P-450,Enzyme, P450,Enzymes, Cytochrome P-450,Enzymes, P-450,Enzymes, P450,Monooxygenase, Cytochrome P-450,Monooxygenase, Cytochrome P-450-Dependent,P 450 Enzyme,P 450 Enzymes,P-450 Enzyme, Cytochrome,P-450 Enzymes, Cytochrome,Superfamily, CYP450,Superfamily, Cytochrome P-450,Superfamily, Cytochrome P450
D001711	Biotransformation	The chemical alteration of an exogenous substance by or in a biological system. The alteration may inactivate the compound or it may result in the production of an active metabolite of an inactive parent compound. The alterations may be divided into METABOLIC DETOXICATION, PHASE I and METABOLIC DETOXICATION, PHASE II.
D014908	Triticum	A plant genus of the family POACEAE that is the source of EDIBLE GRAIN. A hybrid with rye (SECALE CEREALE) is called TRITICALE. The seed is ground into FLOUR and used to make BREAD, and is the source of WHEAT GERM AGGLUTININS.	Wheat,Durum Wheat,Triticum aestivum,Triticum durum,Triticum spelta,Triticum turgidum,Triticum turgidum subsp. durum,Triticum vulgare,Durum Wheats,Wheat, Durum