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
2.1.1.42
-
RECOMMENDED NAME
GeneOntology No.
flavone 3'-O-methyltransferase
REACTION
REACTION DIAGRAM
COMMENTARY
ORGANISM
UNIPROT ACCESSION NO.
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
-
-
-
REACTION TYPE
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
methyl group transfer
-
-
-
-
PATHWAY
KEGG Link
MetaCyc Link
chrysoeriol biosynthesis
-
methylquercetin biosynthesis
-
polymethylated quercetin biosynthesis
-
quercetin sulfate biosynthesis
-
SYSTEMATIC NAME
IUBMB Comments
S-adenosyl-L-methionine:3'-hydroxyflavone 3'-O-methyltransferase
The enzyme prefers flavones with vicinal 3',4'-dihydroxyl groups.
SYNONYMS
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
3'-O-methyltransferase
-
-
caffeic acid/5-hydroxyferulic acid O-methyltransferase
Q9FK25
-
HvOMT1
-
gene name
luteolin 3'-O-methyltransferase
-
-
-
-
luteolin methyltransferase
-
-
-
-
o-dihydric phenol meta-O-methyltransferase
-
-
-
-
o-dihydric phenol methyltransferase
-
-
-
-
o-diphenol m-O-methyltransferase
-
-
-
-
O-methyltransferase
-
-
OMT-15
-
-
OMT-17
-
-
S-adenosylmethionine:flavone/flavonol 3'-O-methyltransferase
-
-
-
-
SOMT-9
-
-
ZmOMT1
-
gene name
CAS REGISTRY NUMBER
COMMENTARY
37205-55-3
-
ORGANISM
COMMENTARY
LITERATURE
SEQUENCE CODE
SEQUENCE DB
SOURCE
soybean, L. var. Mandarin
-
-
Manually annotated by BRENDA team
tobacco, Samsun N N.
-
-
Manually annotated by BRENDA team
SUBSTRATE
PRODUCT                      
REACTION DIAGRAM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
(Substrate)
LITERATURE
(Substrate)
COMMENTARY
(Product)
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
-
?
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
-
-
?
quercetin + S-adenosyl-L-methionine
3'-O-methylquercetin + S-adenosyl-L-homocysteine
show the reaction diagram
-
a flavone, 3'-O-methyltransferase activity, best substrate
i.e. isorhamnetin
-
?
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
-, Q9FK25
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
-
quercetin
-
-
?
S-adenosyl-L-methionine + 3,3',4',5,7-pentahydroxy flavone
S-adenosyl-L-homocysteine + isorhamnetin
show the reaction diagram
-
quercetin
-
-
?
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 + 4,5-dihydroxy-3-methoxycinnamate
S-adenosyl-L-homocysteine + 4-hydroxy-3,5-dimethoxycinnamate
show the reaction diagram
-
5-hydroxy ferulic acid
-
-
?
S-adenosyl-L-methionine + 4,5-dihydroxy-3-methoxycinnamate
S-adenosyl-L-homocysteine + 4-hydroxy-3,5-dimethoxycinnamate
show the reaction diagram
-
5-hydroxy ferulic acid
-
-
?
S-adenosyl-L-methionine + 5,7,3',4'-tetrahydroxyflavanone
S-adenosyl-L-homocysteine + 5,7,4'-trihydroxy-3'-methoxyflavanone
show the reaction diagram
-
eriodictyol
-
-
?
S-adenosyl-L-methionine + 5,7,3',4'-tetrahydroxyflavanone
S-adenosyl-L-homocysteine + 5,7,4'-trihydroxy-3'-methoxyflavanone
show the reaction diagram
-
eriodictyol
-
-
?
S-adenosyl-L-methionine + 5,7,3',4'-tetrahydroxyflavone
S-adenosyl-L-homocysteine + 5,7,4'-trihydroxy-3'-methoxyflavone
show the reaction diagram
-
luteolin
-
-
?
S-adenosyl-L-methionine + 5,7,3',4'-tetrahydroxyflavone
S-adenosyl-L-homocysteine + 5,7,4'-trihydroxy-3'-methoxyflavone
show the reaction diagram
-
luteolin, luteolin, enzyme directly related to flavone glycoside biosynthesis, biosynthesis of 3'-methoxyflavonoids
chrysoeriol
?
S-adenosyl-L-methionine + 5,7,3',4'-tetrahydroxyflavone
S-adenosyl-L-homocysteine + 5,7,4'-trihydroxy-3'-methoxyflavone
show the reaction diagram
-, Q9FK25
i.e. luteolin. 15% of the activity with quercetin
-
-
?
S-adenosyl-L-methionine + 5,7,3',4'-tetrahydroxyflavone
S-adenosyl-L-homocysteine + 3'-O-methylluteolin
show the reaction diagram
-
i.e. luteolin, the enzyme also catalyzes the methylation of tricetin and the methylation of quercetin, prefers tricetin over luteolin
-
-
?
S-adenosyl-L-methionine + 5,7,3',4'-tetrahydroxyflavone
S-adenosyl-L-homocysteine + 3'-O-methylluteolin
show the reaction diagram
-
i.e. lutepolin, the enzyme also catalyzes the methylation of tricetin and the methylation of 5-hydroxyferulic acid and quercetin, prefers tricetin over luteolin
-
-
?
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
-
-
chrysoeriol-7-O-glucoside
?
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
-
luteolin 7-O-glucoside
chrysoeriol-7-O-glucoside
?
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
-
dihydroquercetin
-
-
-
S-adenosyl-L-methionine + dihydro-3,3',4',5,7-pentahydroxy flavone
S-adenosyl-L-homocysteine + dihydroisorhamnetin
show the reaction diagram
-
dihydroquercetin
-
-
?
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
-
poor substrate
-
-
?
taxifolin + S-adenosyl-L-methionine
3'-O-methyl taxifolin + S-adenosyl-L-homocysteine
show the reaction diagram
-
3'-O-methyltransferase activity
-
-
?
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
-
-
?
additional information
?
-
-
-
-
-
-
additional information
?
-
-
isomeric substances isoferulic acid and diosmetin, chrysoeriol, apigenin p-cumaric acid and ferulic acid are not substrates, only ortho-dihydric phenols can function as substrates and only the meta-hydroxyl group is methylated, no reaction takes place if one of the two phenolic hydroxyls is methylated or if only one hydroxyl group is present
-
-
-
additional information
?
-
-
rutin is no substrate
-
-
-
additional information
?
-
-
methylation proceedes only in the meta-position, enzyme is unable to catalyze the methylation of p-coumaric acid, m-coumaric acid, ferulic acid, isoferulic acid, sinapic acid, apigenin and naringenin, isoflavones biochanin A and daidzein do not serve as substrates
-
-
-
additional information
?
-
-
SOMT-9 transfers a methyl group to the 3'-OH group of substrates having ortho-hydroxyl groups and uses a flavonoids as a substrates, no activity with 3,3'-dihydroxyflavone, 5,3'-dihydroxyflavone, 6,3'-dihydroxyflavone, 3'-hydroxyflavone, and 3'-hydroxyflavanone
-
-
-
additional information
?
-
-
OMT-15 and -17 cannot utilize naringenin, apigenin, or kaempferol as substrates, taxifolin and eriodictyol do not serve as methyl acceptors
-
-
-
additional information
?
-
-, Q9FK25
only flavonols with vicinal B-ring hydroxyl groups, such as quercetin and myricetin are good methyl acceptor
-
-
-
NATURAL SUBSTRATES
NATURAL PRODUCTS
REACTION DIAGRAM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
(Substrate)
LITERATURE
(Substrate)
COMMENTARY
(Product)
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
-
-
?
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 ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
S-adenosyl-L-methionine
-
-
METALS and IONS
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
Co2+
-
Co2+ results in recovery of 82% of OMT-15 and 41% of OMT-17 activity compared to the addition of Mg2+
Mg2+
-
required for activity
Mg2+
-
required for activity
Mg2+
-
dependent on
Zn2+
-
Zn2+ results in recovery of less than 10% of OMT-15 and OMT-17 activity compared to the addition of Mg2+
Mn2+
-
the addition of Mn2+ restores 74% of OMT-15 activity and 69% of OMT-17 compared to the addition of Mg2+
additional information
-, Q9FK25
does not require Mg2+
additional information
-
requires no Mg2+
INHIBITORS
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
4-chloromercuribenzoate
-, Q9FK25
5 mM, complete inhibition
NiSO4
-, Q9FK25
5 mM, complete inhibition
S-adenosyl-L-homocysteine
-
inhibits the methylation of luteolin by S-adenosylmethionine
ACTIVATING COMPOUND
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
additional information
-
extractable activity drastically increases by illuminating cells with white light
-
KM VALUE [mM]
KM VALUE [mM] Maximum
SUBSTRATE
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
1.2
-
2-(3,4-dihydroxyphenyl)-5,7-dihydroxy-2,3-dihydro-4H-chromen-4-one
-
-
0.00338
-
3,3',4',5,5',7-hexahydroxyflavone
-, Q9FK25
i.e. mycricetin, 30C, pH not specified in the publication
-
0.00176
-
3,3',4',5,7-pentahydroxyflavone
-, Q9FK25
i.e. quercetin, 30C, pH not specified in the publication
0.075
-
5,7,3',4'-tetrahydroxyflavanone
-
-
0.00618
-
5,7,3',4'-tetrahydroxyflavone
-
30C
0.0159
-
5,7,3',4'-tetrahydroxyflavone
-
30C
0.016
-
5,7,3',4'-tetrahydroxyflavone
-
-
0.046
-
5,7,3'-trihydroxyflavone
-
-
0.028
-
5,7,3'-trihydroxyflavone 7-O-glucoside
-
-
0.031
-
5,7,3'-trihydroxyflavone 7-O-glucoside
-
-
0.227
-
5-hydroxy-3-methoxy-4-hydroxycinnamic acid
-
-
0.035
-
6,7-dihydroxy-3'-methoxyisoflavone
-
-
0.435
-
dihydroquercetin
-
-
0.09
-
luteolin
-
OMT-15, in 10 mM Tris-HCl buffer (pH 7.5), at 37C
0.104
-
luteolin
-
OMT-17, in 10 mM Tris-HCl buffer (pH 7.5), at 37C
0.035
-
quercetin
-
-
0.011
-
S-adenosyl-L-methionine
-
with luteolin as substrate
0.15
-
S-adenosyl-L-methionine
-
with luteolin as substrate
kcat/KM VALUE [1/mMs-1]
kcat/KM VALUE [1/mMs-1] Maximum
SUBSTRATE
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
3
-
3,3',4',5,5',7-hexahydroxyflavone
-, Q9FK25
i.e. mycricetin, 30C, pH not specified in the publication
0
16
-
3,3',4',5,7-pentahydroxyflavone
-, Q9FK25
i.e. quercetin, 30C, pH not specified in the publication
264286
0.000534
-
luteolin
-
OMT-17, in 10 mM Tris-HCl buffer (pH 7.5), at 37C
12694
0.00276
-
luteolin
-
OMT-15, in 10 mM Tris-HCl buffer (pH 7.5), at 37C
12694
SPECIFIC ACTIVITY [µmol/min/mg]
SPECIFIC ACTIVITY MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
0.000027
-
-
-
0.0029
-
-
-
pH OPTIMUM
pH MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
7.5
-
-, Q9FK25
-
7.8
-
-
assay at
8.6
8.9
-
methylation of quercetin
9.6
9.8
-
glycine-NaOH buffer with caffeic acid and luteolin as substrates
pH RANGE
pH RANGE MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
6
10
-
-
TEMPERATURE OPTIMUM
TEMPERATURE OPTIMUM MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
30
-
-
assay at
37
-
-
assay at
pI VALUE
pI VALUE MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
5.48
-
-
calculated from sequence
5.64
-
-
calculated from sequence
SOURCE TISSUE
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
SOURCE
-
OMT-15 is expressed higher in stem and roots than in other tissues
Manually annotated by BRENDA team
-
OMT-17 is expressed in stems only, OMT-15 is expressed higher in stem and roots than in other tissues
Manually annotated by BRENDA team
MOLECULAR WEIGHT
MOLECULAR WEIGHT MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
27800
-
-
OMT-15, calculated from amino acid sequence
30600
-
-
recombinant OMT-17, SDS-PAGE
31100
-
-
recombinant OMT-15, SDS-PAGE
32000
-
-
OMT-17, calculated from amino acid sequence
45000
-
-, Q9FK25
recombinant fusion protein containing a 3 kDa His tail, gel filtration
48000
-
-
gel filtration
SUBUNITS
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
?
-, Q9FK25
1 * 45000, recombinant fusion protein containing a 3 kDa His tail, SDS-PAGE
?
-
x * 64000, recombinant GST-tagged SOMT-9, SDS-PAGE
?
-
x * 38700, calculated from sequence
?
-
x * 39600, calculated from sequence
pH STABILITY
pH STABILITY MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
9.8
-
-
at higher pH values activity rapidly declines
STORAGE STABILITY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
-20C, stored in 10% glycerol for 2 months, no singnificant loss in enzyme activity
-
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
-
4C, stable when stored in buffer containing 10% (v/v) glycerol for 34 weeks
-
-20C, 1-3 mg protein/ml in 0.02 M Tris-HCl buffer loses about 30% of its activity after 1 month
-
4C, acetone powder of fresh cells as source of the enzyme can be kept without significant loss of enzyme activity
-
4C, stable when stored in buffer containing 10% (v/v) glycerol for 3-4 weeks
-
Purification/COMMENTARY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
recombinant GST-tagged SOMT-9 from Escherichia coli to homogeneity
-
glutathione Sepharose 4 column chromatography
-
Cloned/COMMENTARY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
overexpressed in Escherichia coli BL21
-, Q9FK25
SOMT-9, DNA and amino acid sequence determination, expression of GST-tagged SOMT-9 in Escherichia coli
-
expression in Escherichia coli
-
OMT-15 and OMT-17 are expressed in Escherichia coli BL21(DE3) cells as glutathione S-transferase fusion proteins
-
expression in Escherichia coli
-
ENGINEERING
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
D168L
-
the mutation abolishes the enzyme activity of OMT-15
D194L
-
the mutation abolishes the enzyme activity of OMT-15
D209L
-
the mutation abolishes the enzyme activity of OMT-17
D234L
-
the mutation abolishes the enzyme activity of OMT-17
E69L
-
the mutation results in about 14% loss of enzyme activity in OMT-15 and 40% loss of activity in OMT-17
N195I
-
the mutation abolishes the enzyme activity of OMT-15
N235I
-
the mutation abolishes the enzyme activity of OMT-17