A reconstituted microsomal enzyme system that converts naphthalene to trans-1,2-dihydroxy-1,2-dihydronaphthalene via naphthalene-1,2-oxide: Presence of epoxide hydrase in cytochrome P-450 and P-448 fractions

Abstract

Cytochrome P-450 and P-448 fractions isolated from rat liver microsomes contain high levels of epoxide hydrase activity with styrene oxide or naphthalene-1,2-oxide as substrate. A reconstituted system, which consists of cytochrome P-450 or P-448, reductase, and lipid, converts naphthalene into naphthalene-1,2-oxide, trans-1,2-dihydroxy-1,2-dihydronaphthalene and 1-naphthol. The reconstituted stem with cytochrome P-450 produces mainly 1-naphthol, while with cytochrome P-448, nearly equal amounts of dihydrodiol and 1-naphthol are formed. Naphthalene oxide is formed as the intermediate in both systems, and its conversion to dihydrodiol can be blocked by the epoxide hydrase inhibitor, 3,3,3-trichloropropene oxide.