Ian Graham, University of York, UK, and colleagues from GlaxoSmithKline (GSK), Australia, have discovered the gene in poppy plants that is necessary for the synthesis of morphinans. Morphinans are alkaloids which include the painkiller drugs morphine and codeine. Morphinan biosynthesis requires the isomerization of (S)- to (R)-reticuline.
The gene STORR (named for “(S)- to (R)-reticuline”) is only found in poppy species that produce morphinans. STORR evolved with two other genes that result in morphine production. The resulting gene fusion plays a key role in production of morphine. Poppy plant varieties that are unable to produce morphine or codeine carry mutations in the STORR gene that inhibit the morphine production pathway.
The discovery may aid in breeding poppy plants specifically tailored to produce pharmaceutically important morphinans. It could also allow genetically engineering microbes such as yeast to produce morphine.
- Morphinan biosynthesis in opium poppy requires a P450-oxidoreductase fusion protein,
T. Winzer, M. Kern, A. J. King, T. R. Larson, R. Teodor, S. Donninger, Y. Li, A. A. Dowle, J. Cartwright, R. Bates, D. Ashford, J. Thomas, C. Walker, T. A. Bowser, I. A. Graham,