Information on EC 2.1.1.280 - selenocysteine Se-methyltransferase

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The expected taxonomic range for this enzyme is: Eukaryota, Bacteria

EC NUMBER
COMMENTARY hide
2.1.1.280
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RECOMMENDED NAME
GeneOntology No.
selenocysteine Se-methyltransferase
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REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
S-methyl-L-methionine + L-selenocysteine = L-methionine + Se-methyl-L-selenocysteine
show the reaction diagram
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S-methyl-L-methionine + L-selenocysteine = L-methionine + Se-methyl-L-selenocysteine + H+
show the reaction diagram
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PATHWAY
BRENDA Link
KEGG Link
MetaCyc Link
seleno-amino acid detoxification and volatilization III
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SYSTEMATIC NAME
IUBMB Comments
S-methyl-L-methionine:L-selenocysteine Se-methyltransferase
The enzyme uses S-adenosyl-L-methionine as methyl donor less actively than S-methyl-L-methionine. The enzyme from broccoli (Brassica oleracea var. italica) also has the activity of EC 2.1.1.10, homocysteine S-methyltransferase [4].
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
var. italica
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-
Manually annotated by BRENDA team
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UniProt
Manually annotated by BRENDA team
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UniProt
Manually annotated by BRENDA team
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Manually annotated by BRENDA team
a selenium hyperaccumulator plant
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Manually annotated by BRENDA team
strain PCC 7942
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Manually annotated by BRENDA team
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
malfunction
metabolism
physiological function
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
DL-selenocysteine + S-adenosyl-L-methionine
Se-methyl-selenocysteine + S-adenosyl-L-homocysteine
show the reaction diagram
the stereochemical orientation of the alpha-amino group is not crucial. With DL-selenocysteine or DL-selenohomocysteine as substrates, the Km decreases. This leads to the overproportional increase of specific activity with DL-selenocysteine
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-
?
L-selenocysteine + S-adenosyl-L-methionine
Se-methyl-L-selenocysteine + S-adenosyl-L-homocysteine
show the reaction diagram
the enzyme is suitable for specific detoxification of selenocysteine and preventing selenium from intrusion into downstream sulfur pathways. Plays a crucial role in conferring selenium tolerance
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-
?
S-adenosyl-L-methionine + 4-thiobutyric acid
S-adenosyl-L-homocysteine + 4-methylthiobutyric acid
show the reaction diagram
0.014% relative activity compared to activity with L-homocysteine set at 100%
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-
?
S-adenosyl-L-methionine + D-homocysteine
?
show the reaction diagram
16% relative activity compared to activity with L-homocysteine set at 100%
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-
?
S-adenosyl-L-methionine + DL-cysteine
?
show the reaction diagram
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-
-
?
S-adenosyl-L-methionine + DL-homocysteine
?
show the reaction diagram
S-adenosyl-L-methionine + DL-selenocysteine
?
show the reaction diagram
S-adenosyl-L-methionine + DL-selenohomocysteine
?
show the reaction diagram
S-adenosyl-L-methionine + L-cysteine
S-adenosyl-L-homocysteine + S-methyl-L-cysteine
show the reaction diagram
S-adenosyl-L-methionine + L-cysteine
S-methyl-L-cysteine + S-adenosyl-L-homocysteine
show the reaction diagram
1% relative activity with 10 mM L-cysteine compared to 1 mM L-selenocysteine activity set at 100%
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-
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S-adenosyl-L-methionine + L-homocysteine
?
show the reaction diagram
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-
-
?
S-adenosyl-L-methionine + L-homocysteine
S-adenosyl-L-homocysteine + L-methionine
show the reaction diagram
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no activity with wild-type enzyme. A184T mutant enzyme gains the ability to methylate L-homocysteine
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-
?
S-adenosyl-L-methionine + L-homoserine
?
show the reaction diagram
less than 0.003% relative activity compared to activity with L-homocysteine set at 100%
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-
?
S-adenosyl-L-methionine + L-selenocysteine
S-adenosyl-L-homocysteine + Se-methyl-L-selenocysteine
show the reaction diagram
S-adenosyl-L-methionine + L-selenocysteine
Se-methyl-L-selenocysteine + S-adenosyl-L-homocysteine
show the reaction diagram
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-
-
?
S-adenosyl-L-methionine + L-selenohomocysteine
?
show the reaction diagram
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-
-
?
S-adenosyl-L-methionine + selenocysteamine
?
show the reaction diagram
less than 1% relative activity with 1 mM selenocysteamine compared to 1 mM L-selenocysteine activity set at 100%
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S-methyl-L-methionine + DL-selenohomocysteine
?
show the reaction diagram
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-
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?
S-methyl-L-methionine + L-selenocysteine
L-methionine + Se-methyl-L-selenocysteine
show the reaction diagram
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
L-selenocysteine + S-adenosyl-L-methionine
Se-methyl-L-selenocysteine + S-adenosyl-L-homocysteine
show the reaction diagram
P56707
the enzyme is suitable for specific detoxification of selenocysteine and preventing selenium from intrusion into downstream sulfur pathways. Plays a crucial role in conferring selenium tolerance
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-
?
S-adenosyl-L-methionine + L-selenocysteine
S-adenosyl-L-homocysteine + Se-methyl-L-selenocysteine
show the reaction diagram
Q4VNK0
selenate-treated plants synthesize significantly more Se-methyl-L-selenocysteine
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-
?
S-methyl-L-methionine + L-selenocysteine
L-methionine + Se-methyl-L-selenocysteine
show the reaction diagram
additional information
?
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INHIBITORS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
L-methionine
product inhibition above 0.5 mM
L-selenocysteine
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above 1 mM
S-adenosyl-L-methionine
product inhibition above 0.25 mM
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.3
DL-selenocysteine
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pH 6.0, 30C
0.043 - 0.35
DL-selenohomocysteine
0.045 - 0.74
L-homocysteine
0.37 - 0.7
L-selenocysteine
0.015
S-adenosyl-L-methionine
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pH 6.0, 30C
TURNOVER NUMBER [1/s]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.0074 - 0.74
DL-selenohomocysteine
0.38
L-homocysteine
Escherichia coli
Q47690
with [methyl-14C]S-adenosyl-L-methionine, pH 6.5, 30C
0.00017 - 0.0062
L-selenocysteine
kcat/KM VALUE [1/mMs-1]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.021 - 17
DL-selenohomocysteine
7760
8.4
L-homocysteine
Escherichia coli
Q47690
with [methyl-14C]S-adenosyl-L-methionine, pH 6.5, 30C
305
0.00029 - 0.0089
L-selenocysteine
1237
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
0.001
with 10 mM DL-homocysteine as methyl acceptor and [methyl-14C]adenosylmethionine as the methyl donor, pH 7.0 and 25C
0.0011
with 10 mM L-cysteine as methyl acceptor and [methyl-14C]adenosylmethionine as the methyl donor, pH 7.0 and 25C
0.0018
with 10 mM DL-cysteine as methyl acceptor and [methyl-14C]adenosylmethionine as the methyl donor, pH 7.0 and 25C
0.0024
with 0.5 mM L-selenocysteine as methyl acceptor and [methyl-14C]adenosylmethionine as the methyl donor, pH 7.0 and 25C
0.0051
with 0.5 mM DL-selenocysteine as methyl acceptor and [methyl-14C]adenosylmethionine as the methyl donor, pH 7.0 and 25C
0.016
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with [methyl-14C]S-adenosyl-L-methionine, maximal conversion is 10%, pH 6.0, 30C
0.68
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with S-adenosyl-L-methionine, maximal conversion is 20-25%, pH 6.0, 30C
1.5
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with DL-S-methylmethionine, maximal conversion is 50%, pH 6.0, 30C
additional information
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with L-S-methylmethionine, maximal conversion is 100%, pH 6.0, 30C
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE
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cell cultures contain the maximal level of selenocysteine methyltransferase under conditions of exponential growth. Stationary phase cells possess a much lower amount
Manually annotated by BRENDA team
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immunoblotting analysis; of 4-8-week-old seedlings
Manually annotated by BRENDA team
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immunoblotting analysis; of 4-8-week-old seedlings
Manually annotated by BRENDA team
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immunoblotting analysis
Manually annotated by BRENDA team
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immunoblotting analysis; of 4-8-week-old seedlings
Manually annotated by BRENDA team
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY hide
GeneOntology No.
LITERATURE
SOURCE
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
33500
calculated from gene sequence
34000
gel filtration
35000
SDS-PAGE
36700
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calculated from nucleotide sequence
37900
calculated from protein sequence
38000
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gel filtration; SDS-PAGE and gel filtration on a Superdex 75 column
SUBUNITS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
monomer
Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
; by ammonium sulfate precipitation, hydrophobic interaction chromatography and anion exchange chromatography with Q-Sepharose
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; more than 2800fold purification by (NH4)2SO4 precipitation, anion-exchange chromatography and hydrophobic-interaction chromatography
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by ammonium sulfate precipitation, hydrophobic interaction chromatography and anion exchange chromatography with Q-Sepharose; recombinant enzyme
Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
; cloned into plasmid pT7-7 and overexpression in Escherichia coli BL21(DE3) cells
; pUKE vector used for cloning of cDNA sequence coding for the SeCys-methyltransferase from Astragalus bisulcatus in Escherichia coli
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BoSMT overexpression in Escherichia coli strain MTD123
expressed in Escherichia coli
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expressed in Escherichia coli BL21(DE3) cells
expressed in Escherichia coli BL21Star (DE3) cells
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expressed in Escherichia coli Top10 cells
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expressed in Indian mustard plants
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expression in Arabidopsis thaliana
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expression in Nicotiana tabacum
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gene SMT1, expression in Solanum lycopersicum, the transgenic plants are provided with selenite or selenate to the roots during fruit development, they accumulate MeSeCys in the fruits
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generation of enzyme overexpressing lines
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overproduction in Arabidopsis thaliana leads to increased Se accumulation and selenite resistance
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EXPRESSION
ORGANISM
UNIPROT
LITERATURE
concentrations higher than 40 microM show a negative effect on BoSMT mRNA accumulation. At very high selenate concentrations e.g. 100 microM, the expression of BoSMT mRNA substantially reduced; high sulfate levels in growth medium significantly reduce accumulation of BoSMT transcripts in plants
treating Brassica oleracea plants with selenate results in a rapid accumulation of BoSMT mRNA and reaches a maximum expression at selenate levels between 20 and 40 microM. This is in contrast to 40 microM selenite, which causes only a slight accumulation of the transcript
ENGINEERING
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
A184T
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mutant enzyme gains the ability to methylate L-homocysteine
additional information
APPLICATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
agriculture
synthesis