Degradation of Benzo[a]pyrene by Mycobacterium vanbaalenii PYR-1

摘要: Metabolism of the environmental pollutant benzo[a]pyrene in bacterium Mycobacterium vanbaalenii PYR-1 was examined. This organism initially oxidized with dioxygenases and monooxygenases at C-4,5, C-9,10, C-11,12. The metabolites were separated by reversed-phase high-performance liquid chromatography (HPLC) characterized UV-visible, mass, nuclear magnetic resonance, circular dichroism spectral analyses. major intermediates metabolism that had accumulated culture media after 96 h incubation cis-4,5-dihydro-4,5-dihydroxybenzo[a]pyrene (benzo[a]pyrene cis-4,5-dihydrodiol), cis-11,12-dihydro-11,12-dihydroxybenzo[a]pyrene cis-11,12-dihydrodiol), trans-11,12-dihydro-11,12-dihydroxybenzo[a]pyrene trans-11,12-dihydrodiol), 10-oxabenzo[def]chrysen-9-one, hydroxymethoxy dimethoxy derivatives benzo[a]pyrene. ortho-ring fission products 4-formylchrysene-5-carboxylic acid 4,5-chrysene-dicarboxylic a monocarboxylated chrysene product formed when replacement experiments conducted cis-4,5-dihydrodiol. Chiral stationary-phase HPLC analysis dihydrodiols indicated cis-4,5-dihydrodiol 30% 4S,5R 70% 4R,5S absolute stereochemistry. Benzo[a]pyrene cis-11,12-dihydrodiol adopted an 11S,12R conformation 100% optical purity. enantiomeric composition trans-11,12-dihydrodiol equal mixture 11S,12S 11R,12R molecules. results this study, conjunction those previously reported studies, extend pathways proposed for bacterial Our study also provides evidence stereo- regioselectivity oxygenases catalyze M. PYR-1.