Stereoselective fungal metabolism of 7,12-dimethylbenz(a)anthracene: identification and enantiomeric resolution of a K-region dihydrodiol
Syncephalastrum racemosum UT-70 and Cunninghamella elegans ATCC 36112 metabolized 7,12-dimethylbenz(a)anthracene (7,12-DMBA) to hydroxymethyl metabolites as well as 7-hydroxymethyl-12-methylbenz(a)anthracene trans-3,4-, -5,6-, -8,9-, and -10,11-dihydrodiols. The 7,12-DMBA metabolites were isolated by reversed-phase high-performance liquid chromatography and identified by their UV-visible absorption, mass, and nuclear magnetic resonance spectral characteristics. A comparison of the circular dichroism spectra of the K-region (5,6-position) dihydrodiol of both fungal strains with those of the 7,12-DMBA 5S,6S-dihydrodiol formed from 7,12-DMBA by rat liver microsomes indicated that the major enantiomer of the 7-hydroxymethyl-12-methylbenz(a)anthracene trans-5,6-dihydrodiol formed by both fungal strains had a 5R,6R absolute stereochemistry. Direct resolution of the fungal trans-5,6-dihydrodiols by chiral stationary-phase high-performance liquid chromatography indicated that the ratios of the R,R and S,S, enantiomers were 88:12 and 77:23 for S. racemosum and C. elegans, respectively. These results indicate that the fungal metabolism of 7,12-DMBA at the K region (5,6-position) is highly stereoselective and different from that reported for mammalian enzyme systems.
- Research Organization:
- Food and Drug Administration, Jefferson, AR (USA)
- OSTI ID:
- 6939544
- Journal Information:
- Appl. Environ. Microbiol.; (United States), Vol. 53:10
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BENZANTHRACENE
METABOLISM
FUNGI
GENETIC VARIABILITY
LIQUID COLUMN CHROMATOGRAPHY
LIVER
MASS SPECTRA
METABOLITES
MICROSOMES
NUCLEAR MAGNETIC RESONANCE
RATS
ANIMALS
AROMATICS
BIOLOGICAL VARIABILITY
BODY
CELL CONSTITUENTS
CHROMATOGRAPHY
CONDENSED AROMATICS
DIGESTIVE SYSTEM
GLANDS
HYDROCARBONS
MAGNETIC RESONANCE
MAMMALS
ORGANIC COMPOUNDS
ORGANOIDS
ORGANS
PLANTS
RESONANCE
RODENTS
SEPARATION PROCESSES
SPECTRA
VERTEBRATES
560300* - Chemicals Metabolism & Toxicology