Accepted name: 3-O-acetyl-4′-O-demethylpapaveroxine 4′-O-methyltransferase
Reaction: S-adenosyl-L-methionine + 3-O-acetyl-4′-O-demethylpapaveroxine = S-adenosyl-L-homocysteine + 3-O-acetylpapaveroxine
Glossary: 3-O-acetyl-4′-O-demethylpapaveroxine = 6-{(S)-acetoxy[(5R)-4-hydroxy-6-methyl-5,6,7,8-tetrahydro[1,3]dioxolo[4,5-g]isoquinolin-5-yl]methyl}-2,3-dimethoxybenzaldehyde
3-O-acetylpapaveroxine = 6-{(S)-acetoxy[(5R)-4-methoxy-6-methyl-5,6,7,8-tetrahydro[1,3]dioxolo[4,5-g]isoquinolin-5-yl]methyl}-2,3-dimethoxybenzaldehyde
Systematic name: S-adenosyl-L-methionine:3-O-acetyl-4′-O-demethylpapaveroxine 4′-O-methyltransferase
Comments: This activity is part of the noscapine biosynthesis pathway, as characterized in the plant Papaver somniferum (opium poppy). It is catalysed by heterodimeric complexes of the OMT2 gene product and the product of either OMT3 or 6OMT. OMT2 is the catalytic subunit in both complexes.
1.  Li, Y. and Smolke, C.D. Engineering biosynthesis of the anticancer alkaloid noscapine in yeast. Nat. Commun. 7:12137 (2016). [PMID: 27378283]
2.  Park, M.R., Chen, X., Lang, D.E., Ng, K.KS. and Facchini, P.J. Heterodimeric O-methyltransferases involved in the biosynthesis of noscapine in opium poppy. Plant J. 95 (2018) 252–267. [PMID: 29723437]
[EC created 2018]