Information on EC 2.1.1.82 - 3-methylquercetin 7-O-methyltransferase

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The enzyme appears in viruses and cellular organisms

EC NUMBER
COMMENTARY hide
2.1.1.82
-
RECOMMENDED NAME
GeneOntology No.
3-methylquercetin 7-O-methyltransferase
REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
S-adenosyl-L-methionine + 5,7,3',4'-tetrahydroxy-3-methoxyflavone = S-adenosyl-L-homocysteine + 5,3',4'-trihydroxy-3,7-dimethoxyflavone
show the reaction diagram
REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
methyl group transfer
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-
-
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PATHWAY
BRENDA Link
KEGG Link
MetaCyc Link
Flavone and flavonol biosynthesis
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polymethylated quercetin biosynthesis
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polymethylated quercetin glucoside biosynthesis I - quercetin series (Chrysosplenium)
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SYSTEMATIC NAME
IUBMB Comments
S-adenosyl-L-methionine:5,7,3',4'-tetrahydroxy-3-methoxyflavone 7-O-methyltransferase
Involved with EC 2.1.1.76 quercetin 3-O-methyltransferase and EC 2.1.1.83 3,7-dimethylquercetin 4'-O-methyltransferase in the methylation of quercetin to 3,7,4'-trimethylquercetin in Chrysosplenium americanum. Does not act on flavones, dihydroflavonols, or their glucosides.
CAS REGISTRY NUMBER
COMMENTARY hide
96477-62-2
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ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
-
-
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Manually annotated by BRENDA team
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
S-adenosyl-L-methionine + 3',4',5,7-tetrahydroxy-3-methoxyflavone
S-adenosyl-L-homocysteine + 3',4',5-trihydroxy-3,7-dimethoxyflavone
show the reaction diagram
S-adenosyl-L-methionine + kaempferol
7-O-methylkaempferol
show the reaction diagram
-
-
-
-
?
S-adenosyl-L-methionine + quercetin
7-O-methylquercetin
show the reaction diagram
-
-
-
-
?
NATURAL SUBSTRATES
NATURAL PRODUCTS
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
S-adenosyl-L-methionine + 3',4',5,7-tetrahydroxy-3-methoxyflavone
S-adenosyl-L-homocysteine + 3',4',5-trihydroxy-3,7-dimethoxyflavone
show the reaction diagram
-
involved with EC 2.1.1.76 and 2.1.1.83 in the methylation of quercetin
trivial name 3,7-dimethylquercetin
?
INHIBITORS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
Ca2+
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1 mM, 20-50% inhibition
Co2+
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1 mM, 20-50% inhibition
Cu2+
-
1 mM, 20-50% inhibition
p-chloromercuribenzoate
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-
Zn2+
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1 mM, 20-50% inhibition
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.007
3',4',5,7-tetrahydroxy-3-methoxyflavone
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-
0.0324 - 0.0378
kaempferol
0.0298 - 0.0324
quercetin
0.065
S-adenosyl-L-methionine
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TURNOVER NUMBER [1/s]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.064 - 0.07
kaempferol
0.064 - 0.071
quercetin
kcat/KM VALUE [1/mMs-1]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
17 - 19
kaempferol
408
19 - 24
quercetin
137
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
pH RANGE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
7.2 - 9.5
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approx. 50% of maximal activity at pH 7.2 and 9.5
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
57000
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gel filtration
60000
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x * 60000, SDS-PAGE
SUBUNITS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
?
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x * 60000, SDS-PAGE
GENERAL STABILITY
ORGANISM
UNIPROT
LITERATURE
loss of activity during chromatofocusing
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STORAGE STABILITY
ORGANISM
UNIPROT
LITERATURE
-15C, 200 mM potassium phosphate buffer, pH 8, 20% v/v glycerol, 5 mM dithiothreitol, several months, no loss of activity
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-20C, 200 mM Tris-HCl, pH 8.0, 10 mM dithiothreitol, 2 months, no loss of activity
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4C, 4-6 weeks, 80% loss of activity
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Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
ammonium sulfate, gel filtration, chromatofocusing, ion exchange
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GST affinity column chromatography
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loss of activity during chromatofocusing possibly due to instability of the enzyme in the purified form or to the loss of some factors required for activity
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Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
expressed in Escherichia coli BL21 cells
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ENGINEERING
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
D257G
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the mutant methylates the 3-hydroxyl group of flavonols in addition to the 7-hydrdoxyl group
L101M
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the mutant shows wild type reactivity with kaempferol and quercetin