Enzyme morphinone reductase

The Old Yellow Enzyme (OYE) family of flavoproteins consist of a large group of flavin mononucleotide (FMN)-containing NAD(P)H-dependent oxidases. We will describe our work on two of these enzymes morphinone reductase... 

One of the first examples of concurrent oxidation and reduction reactions in a three-enzyme system was reported in 1996 for the biotransformation of morphine to hydromorphone (Scheme 11.2) [6]. Specifically, the NADPH-dependent morphine-6-dehydrogenase (MDH) was coupled to the NADH-dependent morphinone reductase (MR) through the action of a cofactor aspecific (accepting both NADH and NADPH) glutamate dehydrogenase. The latter cofactor regeneration reaction not only allows the use of catalytic amounts of the cofactor but also avoids the accumulation of the reduced cofactor (NADPH) produced by morphine dehydrogenase and the consequent further reduction of hydromorphone to... 

---