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Literature summary for 2.1.1.4 extracted from
- Melatonin biosynthesis requires N-acetylserotonin methyltransferase activity of caffeic acid O-methyltransferase in rice (2015), J. Exp. Bot., 66, 6917-6925.
Cloned(Commentary)
| Cloned (Comment) | Organism |
|---|---|
| gene OsCOMT, recombinant His6-tagged enzyme expression in Escherichia coli strain BL21(DE3), generation of transgenic Nicotiana benthamiana plants and Oryza sativa plants expressing the enzyme using the Agrobacterium tumefaciens strains GV2260 and LBA4404 transfection method | Oryza sativa |
Inhibitors
| Inhibitors | Comment | Organism | Structure |
|---|---|---|---|
| caffeic acid | in vitro N-acetylserotonin methyltransferase activity is significantly and competitively inhibited by caffeic acid, a substrate of the caffeic acid O-methyltransferase, 73% inhibition at 0.01 mM, 93% at 0.1 mM | Oryza sativa |  |
| quercetin | in vitro N-acetylserotonin methyltransferase activity is significantly and competitively inhibited by quercetin, a substrate of the caffeic acid O-methyltransferase, in vivo production of melatonin is significantly inhibited by quercetin in 4-week-old detached rice leaves, 97% inhibition at 0.01 mM, complete inhibition at over 0.05 mM | Oryza sativa | |
KM Value [mM]
| KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
|---|---|---|---|---|---|
| additional information | - |
additional information | Michaelis-Menten kinetics | Oryza sativa | |
| 0.243 | - |
N-acetylserotonin | pH 7.8, 30°C | Oryza sativa | |
Localization
| Localization | Comment | Organism | GeneOntology No. | Textmining |
|---|---|---|---|---|
| cytoplasm | - |
Oryza sativa | 5737 | - |
Natural Substrates/ Products (Substrates)
| Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
|---|---|---|---|---|---|---|
| additional information | Oryza sativa | caffeic acid O-methyltransferase (COMT), EC 2.1.1.68, methylates N-acetylserotonin into melatonin, it has N-acetylserotonin O-methyltransferase (ASMT) activity. The ASMT activity (Vmax/Km) of OsCOMT is 609fold higher than that of rice ASMT1 | ? | - |
? | |
| S-adenosyl-L-methionine + N-acetylserotonin | Oryza sativa | - |
S-adenosyl-L-homocysteine + melatonin | - |
? | |
Organism
| Organism | UniProt | Comment | Textmining |
|---|---|---|---|
| Oryza sativa | Q6ZD89 | cf. EC 2.1.1.42 | - |
Purification (Commentary)
| Purification (Comment) | Organism |
|---|---|
| recombinant His6-tagged enzyme from Escherichia coli strain BL21(DE3) by nickel affinity chromatography | Oryza sativa |
Source Tissue
| Source Tissue | Comment | Organism | Textmining |
|---|---|---|---|
| leaf | - |
Oryza sativa | - |
Substrates and Products (Substrate)
| Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
|---|---|---|---|---|---|---|
| additional information | caffeic acid O-methyltransferase (COMT), EC 2.1.1.68, methylates N-acetylserotonin into melatonin, it has N-acetylserotonin O-methyltransferase (ASMT) activity. The ASMT activity (Vmax/Km) of OsCOMT is 609fold higher than that of rice ASMT1 | Oryza sativa | ? | - |
? | |
| S-adenosyl-L-methionine + N-acetylserotonin | - |
Oryza sativa | S-adenosyl-L-homocysteine + melatonin | - |
? | |
Synonyms
| Synonyms | Comment | Organism |
|---|---|---|
| ASMT | - |
Oryza sativa |
| N-acetylserotonin methyltransferase | - |
Oryza sativa |
Temperature Optimum [°C]
| Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
|---|---|---|---|
| 37 | - |
assay at | Oryza sativa |
pH Optimum
| pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
|---|---|---|---|
| 7.8 | - |
assay at | Oryza sativa |
Cofactor
| Cofactor | Comment | Organism | Structure |
|---|---|---|---|
| S-adenosyl-L-methionine | - |
Oryza sativa | |
General Information
| General Information | Comment | Organism |
|---|---|---|
| malfunction | melatonin production is significantly reduced or increased when the rice plants overexpressed or suppressed the endogenous rice caffeic acid O-methyltransferase | Oryza sativa |
| malfunction | transgenic rice plants overexpressing rice caffeic acid O-methyltransferase/N-acetylserotonin O-methyltransferase show an increase in melatonin levels whereas transgenic rice plants suppressing the rice caffeic acid O-methyltransferase/N-acetylserotonin O-methyltransferase have a significant decrease on melatonin levels | Oryza sativa |
| physiological function | direct role of caffeic acid O-methyltransferase/N-acetylserotonin O-methyltransferase in melatonin biosynthesis in plants | Oryza sativa |
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Release 2023.1 (January 2023)
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