Microsomal and cytosolic cytochrome P450 mediated benzo(a)pyrene hydroxylation in Pleurotus pulmonarius
1995
Masaphy, S. | Levanon, D. | Henis, Y. | Venkateswarlu, K. | Kelly, S.L.
Microsomal and soluble fractions of Pleurotus pulmonarius exhibited a reduced carbon monoxide difference spectrum with P450 maxima at 448 nm and 450-452 nm respectively. Substrate induced Type I spectra were observed on addition of benzo(a)pyrene to both fractions. Benzo(a)pyrene hydroxylation was measured using the aryl hydrocarbon hydroxylase assay and was observed to be P450 dependent as indicated by carbon monoxide inhibition together with the substrate binding characteristics. The activity of the fractions were observed to give Km of 200 mM and 660 mM and Vmax of 1.25 nmol/min/nmol P450 and 0.57 nmol/min/nmol P450 for the microsomal and cytosolic fractions respectively.
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