Isolation of plant cytochrome P-450 and NADPH: cytochrome P-450 reductase from tulip bulbs (Tulipa fosteriana L.) oxidizing xenobiotics.

Cytochrome P-450 and NADPH: cytochrome P-450 reductase were solubilized by detergents from microsomal fraction of tulip bulbs Tulipa fosteriana L. and purified to electrophoretic homogeneity. The purification was achieved by anion-exchange column chromatography, hydroxyapatite-column chromatography and affinity chromatography. The two enzyme showed relative molecular weights of about 54,200 and 77,600 for cytochrome P-450 and NADPH: cytochrome P-450 reductase, respectively. The purified enzymes were characterized by their absorption spectra and by kinetic characteristics. The interaction with endogeneous as well as exogenous substrates was studied by differential spectroscopy. Both enzymes in the presence of dilauroyl phosphatidylcholine and NADPH were able to oxidize xenobiotics (N-nitroso-N-methylaniline and N-nitroso-N-dimethylamine) in the reconstitution experiments.