Enzymes
UniProtKB help_outline | 2 proteins |
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- Name help_outline 3-O-acetylpapaveroxine Identifier CHEBI:141645 Charge 0 Formula C24H27NO8 InChIKeyhelp_outline JUUOWVIBIPDOSQ-IRLDBZIGSA-N SMILEShelp_outline C1=C2CCN([C@](C2=C(C=3OCOC13)OC)([C@H](C=4C=CC(=C(C4C=O)OC)OC)OC(C)=O)[H])C 2D coordinates Mol file for the small molecule Search links Involved in 2 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H2O Identifier CHEBI:15377 (Beilstein: 3587155; CAS: 7732-18-5) help_outline Charge 0 Formula H2O InChIKeyhelp_outline XLYOFNOQVPJJNP-UHFFFAOYSA-N SMILEShelp_outline [H]O[H] 2D coordinates Mol file for the small molecule Search links Involved in 6,048 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline acetate Identifier CHEBI:30089 (Beilstein: 1901470; CAS: 71-50-1) help_outline Charge -1 Formula C2H3O2 InChIKeyhelp_outline QTBSBXVTEAMEQO-UHFFFAOYSA-M SMILEShelp_outline CC([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 165 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H+ Identifier CHEBI:15378 Charge 1 Formula H InChIKeyhelp_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILEShelp_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,176 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline narcotine hemiacetal Identifier CHEBI:141667 Charge 0 Formula C22H25NO7 InChIKeyhelp_outline TZNFGVJRQISOHK-HVHHGIHYSA-N SMILEShelp_outline C1N([C@@](C2=C(C1)C=C3OCOC3=C2OC)([H])[C@@]4(C=5C=CC(=C(C5C(O4)O)OC)OC)[H])C 2D coordinates Mol file for the small molecule Search links Involved in 2 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
RHEA:57400 | RHEA:57401 | RHEA:57402 | RHEA:57403 | |
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Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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MetaCyc help_outline |
Publications
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Heterodimeric O-methyltransferases involved in the biosynthesis of noscapine in opium poppy.
Park M.R., Chen X., Lang D.E., Ng K.K.S., Facchini P.J.
Noscapine biosynthesis in opium poppy involves three characterized O-methyltransferases (OMTs) and a fourth responsible for the 4'-methoxyl on the phthalide isoquinoline scaffold. The first three enzymes are homodimers, whereas the latter is a heterodimer encoded by two linked genes (OMT2 and OMT3 ... >> More
Noscapine biosynthesis in opium poppy involves three characterized O-methyltransferases (OMTs) and a fourth responsible for the 4'-methoxyl on the phthalide isoquinoline scaffold. The first three enzymes are homodimers, whereas the latter is a heterodimer encoded by two linked genes (OMT2 and OMT3). Neither OMT2 nor OMT3 form stable homodimers, but yield a substrate-specific heterodimer when their genes are co-expressed in Escherichia coli. The only substrate, 4'-O-desmethyl-3-O-acetylpapaveroxine, is a seco-berbine pathway intermediate that undergoes ester hydrolysis subsequent to 4'-O-methylation leading to the formation of narcotine hemiacetal. In the absence of 4'-O-methylation, a parallel pathway yields narcotoline hemiacetal. Dehydrogenation produces noscapine and narcotoline from the corresponding hemiacetals. Phthalide isoquinoline intermediates with a 4'-hydroxyl (i.e. narcotoline and narcotoline hemiacetal), or the corresponding 1-hydroxyl on protoberberine intermediates, were not accepted. Norcoclaurine 6OMT, which shares 81% amino acid sequence identity with OMT3, also formed a functionally similar heterodimer with OMT2. Suppression of OMT2 transcript levels in opium poppy increased narcotoline accumulation, whereas reduced OMT3 transcript abundance caused no detectable change in the alkaloid phenotype. Opium poppy chemotype Marianne accumulates high levels of narcotoline and showed no detectable OMT2:OMT3 activity. Compared with the active subunit from the Bea's Choice chemotype, Marianne OMT2 exhibited a single S122Y mutation in the dimerization domain that precluded heterodimer formation based on homology models. Both subunits contributed to the formation of the substrate-binding domain, although site-directed mutagenesis revealed OMT2 as the active subunit. The occurrence of physiologically relevant OMT heterodimers increases the catalytic diversity of enzymes derived from a smaller number of gene products. << Less
Plant J. 95:252-267(2018) [PubMed] [EuropePMC]
This publication is cited by 3 other entries.
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Acetylation serves as a protective group in noscapine biosynthesis in opium poppy.
Dang T.T., Chen X., Facchini P.J.
We have characterized four sequential enzymes that transform 1-hydroxy-N-methylcanadine to narcotoline hemiacetal, completing our elucidation of noscapine biosynthesis in opium poppy. Two cytochromes P450 catalyze hydroxylations at C13 and C8 on the protoberberine scaffold, the latter step inducin ... >> More
We have characterized four sequential enzymes that transform 1-hydroxy-N-methylcanadine to narcotoline hemiacetal, completing our elucidation of noscapine biosynthesis in opium poppy. Two cytochromes P450 catalyze hydroxylations at C13 and C8 on the protoberberine scaffold, the latter step inducing ring opening and the formation of an aldehyde moiety. Acetylation at C13 before C8 hydroxylation introduces a protective group subsequently hydrolyzed by a carboxylesterase, which triggers rearrangement to a cyclic hemiacetal. << Less
Nat. Chem. Biol. 11:104-106(2015) [PubMed] [EuropePMC]
This publication is cited by 5 other entries.