CYTOCHROME-P-450 FROM TULIP BULBS (TULIPA-FOSTERIANA L) OXIDIZES AN AZO-DYE SUDAN-I (1-PHENYLAZO-2-HYDROXYNAPHTHALENE, SOLVENT-YELLOW-14) IN-VITRO

The microsomal fraction from tulip bulbs (Tulipa fosteriana L.) contai ns cytochrome P-450 enzymes catalyzing the NADPH-dependent oxidation o f the xenobiotic substrate, an azo dye Sudan I (1-phenylazo-2-hydroxyn aphthalene, Solvent Yellow 14). C-Hydroxy derivatives [1-(4-hydroxyphe nylazo)-2-hydroxynaphthalene, 1-phenylazo-2,6-dihydroxynaphthalene, 1- (4-hydroxyphenylazo)-2,6-dihydroxynaphthalene] and the benzenediazoniu m ion are the products of the Sudan I oxidation. The oxidation of Suda n I has also been assessed in a reconstituted electron-transport chain with the isolated cytochrome P-450, isolated plant NADPH-cytochrome P -450 reductase and phospholipid. The results are discussed from the po int of view of the role of cytochromes P-450 in the metabolism of xeno biotics in plants.