Publications

• Acetyl coenzyme A:salutaridinol-7-O-acetyltransferase from Papaver somniferum plant cell cultures. The enzyme catalyzing the formation of thebaine in morphine biosynthesis.

  Lenz R., Zenk M.H.

  Acetyl coenzyme A:salutaridinol-7-O-acetyltransferase, a highly substrate-specific enzyme, has been purified nearly 3,000-fold to homogeneity from Papaver somniferum plant cell suspension cultures. Purification was achieved by fractionated ammonium sulfate precipitation, dye-ligand affinity chroma ... >> More

  Acetyl coenzyme A:salutaridinol-7-O-acetyltransferase, a highly substrate-specific enzyme, has been purified nearly 3,000-fold to homogeneity from Papaver somniferum plant cell suspension cultures. Purification was achieved by fractionated ammonium sulfate precipitation, dye-ligand affinity chromatography on matrex red A, gel filtration, ion exchange chromatography on Mono Q and a second dye-ligand affinity chromatography on fractogel TSK AF Blue. The purified enzyme was a single polypeptide with an M(r) = 50,000 displaying an isoelectric point of 4.8, a pH optimum between pH 6 and 9 and a temperature optimum at 47 degrees C. The Km values for the substrate salutaridinol and the co-substrate acetyl co-enzyme A were 7 and 46 microM, respectively. Salutaridinol-7-O-acetyltransferase catalyzes the stoichiometric transfer of the acetyl group from acetyl coenzyme A to the 7-OH group of salutaridinol yielding salutaridinol-7-O-acetate, which is a new intermediate in morphine biosynthesis. Salutaridinol-7-O-acetate undergoes a subsequent spontaneous allylic elimination at pH 8-9, leading to the formation of thebaine (1), the first morphinan alkaloid with the complete pentacyclic ring system, or at pH 7 leading to dibenz[d,f]azonine alkaloids that contain a nine-membered ring. Acetylation and subsequent allylic elimination is a new enzymic mechanism in alkaloid biosynthesis, which in the poppy plant can transform one precursor into alkaloids possessing markedly different ring systems, depending on the reaction pH. << Less

  J. Biol. Chem. 270:31091-31096(1995) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Molecular characterization of the salutaridinol 7-O-acetyltransferase involved in morphine biosynthesis in Opium poppy Papaver somniferum.

  Grothe T., Lenz R., Kutchan T.M.

  Salutaridinol 7-O-acetyltransferase (EC ) catalyzes the conversion of the phenanthrene alkaloid salutaridinol to salutaridinol-7-O-acetate, the immediate precursor of thebaine along the morphine biosynthetic pathway. We have isolated a cDNA clone that corresponds to the internal amino acid sequenc ... >> More

  Salutaridinol 7-O-acetyltransferase (EC ) catalyzes the conversion of the phenanthrene alkaloid salutaridinol to salutaridinol-7-O-acetate, the immediate precursor of thebaine along the morphine biosynthetic pathway. We have isolated a cDNA clone that corresponds to the internal amino acid sequences of the native enzyme purified from a cell suspension culture of opium poppy Papaver somniferum. The recombinant enzyme acetylated the 7-hydroxyl moiety of salutaridinol in the presence of acetyl-CoA. The apparent K(m) value for salutaridinol was determined to be 9 microm and 54 microm for acetyl-CoA. The gene transcript was detected in extracts from Papaver orientale and Papaver bracteatum in addition to P. somniferum. Genomic DNA gel blot analysis indicated that there is likely a single copy of this gene in the P. somniferum genome. The amino acid sequence of salutaridinol 7-O-acetyltransferase is most similar (37% identity) to that of deacetylvindoline acetyltransferase of Catharanthus roseus. Salutaridinol 7-O-acetyltransferase is the second enzyme specific to morphine biosynthesis for which we have isolated a cDNA. Taken together with the other cDNAs cloned encoding norcoclaurine 6-O-methyltransferase, (S)-N-methylcoclaurine 3'-hydroxylase, the cytochrome P-450 reductase, and codeinone reductase, significant progress has been made toward accumulating genes of this pathway to enable the end goal of a biotechnological production of morphinan alkaloids. << Less

  J. Biol. Chem. 276:30717-30723(2001) [PubMed] [EuropePMC]