Molecular characterization of the salutaridinol 7-O-acetyltransferase involved in morphine biosynthesis in opium poppy Papaver somniferum.
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.
Grothe
T
T
Leibniz-Institut für Pflanzenbiochemie, Weinberg 3, 06120 Halle/Saale, Germany.
Lenz
R
R
Kutchan
T M
TM
D000123:Acetyltransferases / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D000595:Amino Acid Sequence; D018076:DNA, Complementary / Q000737:chemistry; D008969:Molecular Sequence Data; D009020:Morphine / Q000378:metabolism*; D009892:Opium / Q000378:metabolism*; D011994:Recombinant Proteins / Q000302:isolation & purification
D018076:DNA, Complementary; D011994:Recombinant Proteins; D009020:Morphine; D009892:Opium; D000123:Acetyltransferases; C097501:acetyl coenzyme A-salutaridinol-7-O-acetyltransferase