The enzyme is present in the poppy, Papaver somniferum. At pH 8-9 the product, 7-O-acetylsalutaridinol, spontaneously closes the 4→5 oxide bridge by allylic elimination to form the morphine precursor thebaine
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Lenz, R., Zenk, M.H. Acetyl-CoA:salutaridinol 7-O-acetyltransferase from Papaver somniferum plant cell cultures. The enzyme catalyzing the formation of thebaine in morphine biosynthesis. J. Biol. Chem.270 (1995) 31091–31096. [PMID: 8537369]