Information on EC 2.1.1.42 - flavone 3'-O-methyltransferase

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The expected taxonomic range for this enzyme is: Magnoliophyta

EC NUMBER
COMMENTARY hide
2.1.1.42
-
RECOMMENDED NAME
GeneOntology No.
flavone 3'-O-methyltransferase
REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
S-adenosyl-L-methionine + 3'-hydroxyflavone = S-adenosyl-L-homocysteine + 3'-methoxyflavone
show the reaction diagram
also acts on luteolin 7-O-beta-D-glucoside
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-
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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
chrysoeriol biosynthesis
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Flavone and flavonol biosynthesis
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methylquercetin biosynthesis
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phenylpropanoids methylation (ice plant)
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polymethylated quercetin biosynthesis
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quercetin sulfate biosynthesis
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SYSTEMATIC NAME
IUBMB Comments
S-adenosyl-L-methionine:3'-hydroxyflavone 3'-O-methyltransferase
The enzyme prefers flavones with vicinal 3',4'-dihydroxyl groups.
CAS REGISTRY NUMBER
COMMENTARY hide
37205-55-3
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ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
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-
-
Manually annotated by BRENDA team
tobacco, Samsun N N.
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Manually annotated by BRENDA team
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Manually annotated by BRENDA team
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Manually annotated by BRENDA team
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
physiological function
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an Arabidopsis thaliana knockout mutant exhibits less production of melatonin than the wild type when leaves are infiltrated with 1 mM N-acetylserotonin
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
luteolin + S-adenosyl-L-methionine
3'-O-methyl luteolin + S-adenosyl-L-homocysteine
show the reaction diagram
-
high 3'-O-methyltransferase activity
i.e. chrysoeriol
-
?
luteolin + S-adenosyl-L-methionine
3'-O-methylluteolin + S-adenosyl-L-homocysteine
show the reaction diagram
-
OMT-15 shows 92% activity and OMT-17 shows 84% activity compared to myricetin
-
-
?
quercetin + S-adenosyl-L-methionine
3'-O-methylquercetin + S-adenosyl-L-homocysteine
show the reaction diagram
S-adenosyl-L-methionine + 3,3',4',5,5',7-hexahydroxyflavone
S-adenosyl-L-homocysteine + 3,4',5,5',7-pentahydroxy-3'-methoxyflavone
show the reaction diagram
i.e. mycricetin. 70% of the activity with quercetin
-
-
?
S-adenosyl-L-methionine + 3,3',4',5,7-pentahydroxy flavone
S-adenosyl-L-homocysteine + isorhamnetin
show the reaction diagram
S-adenosyl-L-methionine + 3,3',4',5,7-pentahydroxyflavone
S-adenosyl-L-homocysteine + 3,4',5,7-tetrahydroxy-3'-methoxyflavone
show the reaction diagram
i.e. quercetin. Preferred substrate
i.e. isorhamnetin
-
?
S-adenosyl-L-methionine + 4,5-dihydroxy-3-methoxycinnamate
S-adenosyl-L-homocysteine + 4-hydroxy-3,5-dimethoxycinnamate
show the reaction diagram
S-adenosyl-L-methionine + 5,7,3',4'-tetrahydroxyflavanone
S-adenosyl-L-homocysteine + 5,7,4'-trihydroxy-3'-methoxyflavanone
show the reaction diagram
S-adenosyl-L-methionine + 5,7,3',4'-tetrahydroxyflavone
S-adenosyl-L-homocysteine + 3'-O-methylluteolin
show the reaction diagram
S-adenosyl-L-methionine + 5,7,3',4'-tetrahydroxyflavone
S-adenosyl-L-homocysteine + 5,7,4'-trihydroxy-3'-methoxyflavone
show the reaction diagram
S-adenosyl-L-methionine + 5,7,3'-trihydroxyflavone 7-O-glucoside
S-adenosyl-L-homocysteine + 5,7,4'-trihydroxy-3'-methoxyflavone 7-O-glucoside
show the reaction diagram
S-adenosyl-L-methionine + 5-hydroxyferulic acid
?
show the reaction diagram
-
OMT-15 shows 25% activity and OMT-17 shows 18% activity compared to myricetin
-
-
?
S-adenosyl-L-methionine + 7,8-dihydroxyflavone
?
show the reaction diagram
-
OMT-15 shows 102% activity and OMT-17 shows 143% activity compared to myricetin
-
-
?
S-adenosyl-L-methionine + dihydro-3,3',4',5,7-pentahydroxy flavone
S-adenosyl-L-homocysteine + dihydroisorhamnetin
show the reaction diagram
S-adenosyl-L-methionine + quercetin 3-O-glucoside
S-adenosyl-L-homocysteine + ?
show the reaction diagram
-
poor substrate
-
-
?
S-adenosyl-L-methionine + rutin
S-adenosyl-L-homocysteine + ?
show the reaction diagram
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poor substrate
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-
?
taxifolin + S-adenosyl-L-methionine
3'-O-methyl taxifolin + S-adenosyl-L-homocysteine
show the reaction diagram
-
3'-O-methyltransferase activity
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-
?
additional information
?
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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
quercetin + S-adenosyl-L-methionine
3'-O-methylquercetin + S-adenosyl-L-homocysteine
show the reaction diagram
-
SOMT-9 is involved in the biosynthesis of isorhamnetin
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-
?
S-adenosyl-L-methionine + 3,3',4',5,7-pentahydroxyflavone
S-adenosyl-L-homocysteine + 3,4',5,7-tetrahydroxy-3'-methoxyflavone
show the reaction diagram
Q9FK25
i.e. quercetin. Preferred substrate
i.e. isorhamnetin
-
?
S-adenosyl-L-methionine + 5,7,3',4'-tetrahydroxyflavone
S-adenosyl-L-homocysteine + 5,7,4'-trihydroxy-3'-methoxyflavone
show the reaction diagram
-
luteolin, enzyme directly related to flavone glycoside biosynthesis, biosynthesis of 3'-methoxyflavonoids
chrysoeriol
?
COFACTOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
S-adenosyl-L-methionine
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METALS and IONS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
Co2+
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Co2+ results in recovery of 82% of OMT-15 and 41% of OMT-17 activity compared to the addition of Mg2+
Mn2+
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the addition of Mn2+ restores 74% of OMT-15 activity and 69% of OMT-17 compared to the addition of Mg2+
Zn2+
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Zn2+ results in recovery of less than 10% of OMT-15 and OMT-17 activity compared to the addition of Mg2+
additional information
INHIBITORS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
4-chloromercuribenzoate
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5 mM, complete inhibition
NiSO4
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5 mM, complete inhibition
S-adenosyl-L-homocysteine
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inhibits the methylation of luteolin by S-adenosylmethionine
ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
additional information
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extractable activity drastically increases by illuminating cells with white light
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KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
1.2
2-(3,4-dihydroxyphenyl)-5,7-dihydroxy-2,3-dihydro-4H-chromen-4-one
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-
0.00338
3,3',4',5,5',7-hexahydroxyflavone
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i.e. mycricetin, 30C, pH not specified in the publication
0.00176
3,3',4',5,7-pentahydroxyflavone
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i.e. quercetin, 30C, pH not specified in the publication
0.075
5,7,3',4'-tetrahydroxyflavanone
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-
0.00618 - 0.016
5,7,3',4'-tetrahydroxyflavone
0.046
5,7,3'-trihydroxyflavone
-
-
0.028 - 0.031
5,7,3'-trihydroxyflavone 7-O-glucoside
0.227
5-hydroxy-3-methoxy-4-hydroxycinnamic acid
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-
0.035
6,7-dihydroxy-3'-methoxyisoflavone
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-
0.435
dihydroquercetin
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0.09 - 0.104
luteolin
0.035
quercetin
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0.011 - 0.15
S-adenosyl-L-methionine
kcat/KM VALUE [1/mMs-1]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
3
3,3',4',5,5',7-hexahydroxyflavone
Arabidopsis thaliana
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i.e. mycricetin, 30C, pH not specified in the publication
84023
16
3,3',4',5,7-pentahydroxyflavone
Arabidopsis thaliana
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i.e. quercetin, 30C, pH not specified in the publication
37996
0.000534 - 0.00276
luteolin
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
0.0029
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pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
7.8
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assay at
8.6 - 8.9
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methylation of quercetin
9.6 - 9.8
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glycine-NaOH buffer with caffeic acid and luteolin as substrates
pH RANGE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
6 - 10
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TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
37
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assay at
pI VALUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
5.48
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calculated from sequence
5.64
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calculated from sequence
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
27800
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OMT-15, calculated from amino acid sequence
30600
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recombinant OMT-17, SDS-PAGE
31100
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recombinant OMT-15, SDS-PAGE
32000
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OMT-17, calculated from amino acid sequence
45000
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recombinant fusion protein containing a 3 kDa His tail, gel filtration
48000
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gel filtration
SUBUNITS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
pH STABILITY
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
9.8
-
at higher pH values activity rapidly declines
485342
STORAGE STABILITY
ORGANISM
UNIPROT
LITERATURE
-20C, 1-3 mg protein/ml in 0.02 M Tris-HCl buffer loses about 30% of its activity after 1 month
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-20C, stored in 10% glycerol for 2 months, no singnificant loss in enzyme activity
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4C, acetone powder of fresh cells as source of the enzyme can be kept without significant loss of enzyme activity
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4C, highly unstable, stored with Triton X-100, bovine serum albumin, ethylene glycol, dimethyl sulfoxide, 2-mercaptoethanol, dithiothreitol or ethylene glycol monoethylether, loses over 90% of its activity within 94 h
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4C, stable when stored in buffer containing 10% (v/v) glycerol for 3-4 weeks
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4C, stable when stored in buffer containing 10% (v/v) glycerol for 34 weeks
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Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
glutathione Sepharose 4 column chromatography
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recombinant GST-tagged SOMT-9 from Escherichia coli to homogeneity
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Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
expression in Escherichia coli
OMT-15 and OMT-17 are expressed in Escherichia coli BL21(DE3) cells as glutathione S-transferase fusion proteins
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overexpressed in Escherichia coli BL21
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SOMT-9, DNA and amino acid sequence determination, expression of GST-tagged SOMT-9 in Escherichia coli
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ENGINEERING
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
D168L
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the mutation abolishes the enzyme activity of OMT-15
D194L
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the mutation abolishes the enzyme activity of OMT-15
D209L
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the mutation abolishes the enzyme activity of OMT-17
D234L
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the mutation abolishes the enzyme activity of OMT-17
E69L
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the mutation results in about 14% loss of enzyme activity in OMT-15 and 40% loss of activity in OMT-17
N195I
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the mutation abolishes the enzyme activity of OMT-15
N235I
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the mutation abolishes the enzyme activity of OMT-17