Fungal oxidation of benzo(a)pyrene and (+-)-trans-7,8-dihydroxy-7,8-dihydrobenzo(a)pyrene
The oxidation of benzo(a)pyrene by intact cells of the filamentous fungus Cunninghamella elegans resulted in the formation of a complex mixture of polar products which were detected by high pressure liquid chromatography. One of the products had a retention time on high pressure liquid chromatography identical with that given by (+-)-7..beta..,8a,9a,10..beta..-tetrahydroxy-7,8,9,10-tetrahydrobenzo(a)pyrene. In addition the absorption and mass spectra given by the fungal metabolite were consistent with this structural assignment. Incubation of (+-)-trans-7,8-dihydrobenzo(a)pyrene with cells of C. elegans led to the formation of the same tetrahydroxymetabolite. Two other products were formed that were identified as new phenolic derivatives of (+-)-trans-7,8-dihydroxy-7,8-dihydrobenzo(a)pyrene. Experiments with (+-)-trans (G-/sup 3/H) 7,8-dihydrobenzo(a)pyrene showed that over a 12-h period 4.0% of the dihydrodiol was converted to ethyl acetate-soluble products and 7..beta..,8..cap alpha..,9..cap alpha..,10..beta..-tetrahydroxy-7,8,9,10-tetrahdrobenzo(a)pyrene accounted for 25% of these metabolites. The results suggest that C. elegans can oxidize benzo(a)pyrene to either (+-)-7..beta..,8..cap alpha..-dihydroxy-9..cap alpha..,10..cap alpha..-epoxy-7,8,9,10-tetrahydroxy(a)pyrene or one of the two possible enantiomers of this compound. Under the experimental conditions, no evidence was found to suggest the formation of (+-)-7..beta..,8..cap alpha..-dihydroxy-9..beta..,10..beta..-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene. Thus, C. elegans has the ability to form at least one of the two diastereomeric benzo(a)pyrene 7,8-diol-9,10-epoxides that have been implicated as the ultimate carcinogenic forms of benzo(a)pyrene in higher organisms.
- Research Organization:
- Univ. of Texas, Austin
- OSTI ID:
- 5098774
- Journal Information:
- J. Biol. Chem.; (United States), Vol. 255:11
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
BENZOPYRENE
OXIDATION
FUNGI
METABOLISM
BIOCHEMICAL REACTION KINETICS
EPOXIDES
METABOLITES
QUALITATIVE CHEMICAL ANALYSIS
AROMATICS
CHEMICAL ANALYSIS
CHEMICAL REACTIONS
CONDENSED AROMATICS
HYDROCARBONS
KINETICS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PLANTS
REACTION KINETICS
560302* - Chemicals Metabolism & Toxicology- Microorganisms- (-1987)
550200 - Biochemistry
550700 - Microbiology