Catalyzes the dehydrogenation of morphine to morphinone. The enzyme also exhibits significant activity for a variety of cyclic and alicyclic alcohols. In addition to xenobiotics, the enzyme catalyzes the dehydrogenation of 17-beta-hydroxysteroids with much higher affinities than morphine. Uses both NAD and NADP, but the activity is much greater with NAD than with NADP. morphine + NAD(+) = H(+) + morphinone + NADH morphine + NADP(+) = H(+) + morphinone + NADPH Strongly inhibited by sulfhydryl reagents and ketamine, but not by pyrazole, barbital and indomethacine. Optimum pH is 9.3 with NAD as the cofactor. Monomer. The N-terminus is blocked. Belongs to the aldo/keto reductase family.