IUBMB Enzyme Nomenclature


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

For diagram of reaction click here.

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.

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:


1. Li, Y. and Smolke, C.D. Engineering biosynthesis of the anticancer alkaloid noscapine in yeast. Nat Commun 7 (2016) 12137. [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]

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