Evidence for cytochrome P-450 and P-450-mediated benzo(a) pyrene hydroxylation in the white rot fungus Phanerochaete chrysosporium |
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Authors: | Segula Masaphy Dan Levanon Yigal Henis K Venkateswarlu Steven L Kelly |
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Institution: | MIGAL Technology Centre, Kiryat Shmona 10200, Israel; Faculty of Agriculture, Hebrew University, Rehovot 76100, Israel; Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, Sheffield University, Sheffield S10 2UH, UK |
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Abstract: | Abstract The presence of cytochrome P-450 and P-450-mediated benzo(a)pyrene hydroxylase activity in both microsomal and soluble fractions of the white rot fungus Phanerochaete chrysosporium was shown. The reduced carbon monoxide difference spectrum showed maxima at 448–450 and 452–454 nm for microsomal and cytosolic fractions, respectively. Both P-450 fractions produced a Type I substrate binding spectrum on addition of benzo(a)pyrene. Activity for benzo(a)pyrene hydroxylation was NADPH-dependent and inhibited by carbon monoxide. K m values for activity showed a difference between the cellular fractions with a K m of 89 μM for microsomal P-450 and 400 μM for cytosolic P-450. The V max values observed were 0.83 nmol min? (nmol microsomal P-450) ?1 and 0.4 nmol min?1 (nmol cytosolic P-450)?1. The results indicate that P-450-mediated benzo(a)pyrene hydroxylase activity could play a role in xenobiotic transformation by this fungus beside the known ligninolytic exocellular enzymes. |
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Keywords: | Phanerochaete chrysosporium Cytochrome P-450 Bioremediation |
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