Reaction participants Show >> << Hide
- Name help_outline 7,8-dihydroxycoumarin Identifier CHEBI:17313 (CAS: 486-35-1) help_outline Charge 0 Formula C9H6O4 InChIKeyhelp_outline ATEFPOUAMCWAQS-UHFFFAOYSA-N SMILEShelp_outline C12=C(C=CC(=C1O)O)C=CC(O2)=O 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 S-adenosyl-L-methionine Identifier CHEBI:59789 Charge 1 Formula C15H23N6O5S InChIKeyhelp_outline MEFKEPWMEQBLKI-AIRLBKTGSA-O SMILEShelp_outline C[S+](CC[C@H]([NH3+])C([O-])=O)C[C@H]1O[C@H]([C@H](O)[C@@H]1O)n1cnc2c(N)ncnc12 2D coordinates Mol file for the small molecule Search links Involved in 938 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline 7-hydroxy-8-methoxycoumarin Identifier CHEBI:180544 Charge 0 Formula C10H8O4 InChIKeyhelp_outline HAQWEMHXSIRYBE-UHFFFAOYSA-N SMILEShelp_outline C12=C(C=CC(=C1OC)O)C=CC(O2)=O 2D coordinates Mol file for the small molecule Search links Involved in 1 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline S-adenosyl-L-homocysteine Identifier CHEBI:57856 Charge 0 Formula C14H20N6O5S InChIKeyhelp_outline ZJUKTBDSGOFHSH-WFMPWKQPSA-N SMILEShelp_outline Nc1ncnc2n(cnc12)[C@@H]1O[C@H](CSCC[C@H]([NH3+])C([O-])=O)[C@@H](O)[C@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 854 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 9,932 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:68960 | RHEA:68961 | RHEA:68962 | RHEA:68963 | |
|---|---|---|---|---|
| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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| Gene Ontology help_outline | ||||
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Publications
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Daphnetin methylation by a novel O-methyltransferase is associated with cold acclimation and photosystem II excitation pressure in rye.
N'Dong C., Anzellotti D., Ibrahim R.K., Huner N.P.A., Sarhan F.
In plants, O-methylation of phenolic compounds plays an important role in such processes as lignin synthesis, flower pigmentation, chemical defense, and signaling. However, apart from phenylpropanoids and flavonoids, very few enzymes involved in coumarin biosynthesis have been identified. We repor ... >> More
In plants, O-methylation of phenolic compounds plays an important role in such processes as lignin synthesis, flower pigmentation, chemical defense, and signaling. However, apart from phenylpropanoids and flavonoids, very few enzymes involved in coumarin biosynthesis have been identified. We report here the molecular and biochemical characterization of a gene encoding a novel O-methyltransferase that catalyzes the methylation of 7,8-dihydroxycoumarin, daphnetin. The recombinant protein displayed an exclusive methylation of position 8 of daphnetin. The identity of the methylated product was unambiguously identified as 7-hydroxy-8-methoxycoumarin by co-chromatography on cellulose TLC and coelution from high performance liquid chromatography, with authentic synthetic samples, as well as by UV, mass spectroscopy, (1)H NMR spectral analysis, and NOE correlation signals of the relevant protons. Northern blot analysis and enzyme activity assays revealed that the transcript and corresponding enzyme activity are up-regulated by both low temperature and photosystem II excitation pressure. Using various phenylpropanoid and flavonoid substrates, we demonstrate that cold acclimation of rye leaves increases O-methyltransferase activity not only for daphnetin but also for the lignin precursors, caffeic acid, and 5-hydroxyferulic acid. The significance of this novel enzyme and daphnetin O-methylation is discussed in relation to its putative role in modulating cold acclimation and photosystem II excitation pressure. << Less