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Information on EC 2.1.1.137 - arsenite methyltransferase and Organism(s) Rattus norvegicus and UniProt Accession Q8VHT6

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EC Tree
     2 Transferases
         2.1 Transferring one-carbon groups
             2.1.1 Methyltransferases
                2.1.1.137 arsenite methyltransferase
IUBMB Comments
An enzyme responsible for synthesis of trivalent methylarsenical antibiotics in microbes or detoxification of inorganic arsenous acid in animals. The in vivo substrate is arsenic triglutathione or similar thiol (depending on the organism) , from which the arsenic is transferred to the enzyme forming bonds with the thiol groups of three cysteine residues via a disulfide bond cascade pathway [7, 8]. Most of the substrates undergo two methylations and are converted to dimethylarsinous acid . However, a small fraction are released earlier as methylarsonous acid, and a smaller amount proceeds via a third methylation, resulting in the volatile product trimethylarsane. Methylation involves temporary oxidation to arsenic(V) valency, followed by reduction back to arsenic(III) valency using electrons provided by thioredoxin or a similar reduction system. The arsenic(III) products are quickly oxidized in the presence of oxygen to the corresponding arsenic(V) species.
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Rattus norvegicus
UNIPROT: Q8VHT6
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The taxonomic range for the selected organisms is: Rattus norvegicus
The expected taxonomic range for this enzyme is: Bacteria, Eukaryota, Archaea
Synonyms
as3mt, arsenic (+3 oxidation state) methyltransferase, n6amt1, has3mt, arsenite methyltransferase, cyt19, as(iii) s-adenosylmethionine methyltransferase, arsenic (iii) methyltransferase, arsenite s-adenosylmethionine methyltransferase, arsenic (+3) methyltransferase, more
SYNONYM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
AdoMet:arsenic(III) methyltransferase
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arsenic (+3 oxidation state) methyltransferase
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S-adenosyl-L-methionine:arsenic(III) methyltransferase
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arsenic (+3 oxidation state) methyltransferase
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arsenic (+3 oxidation state)-methyltransferase
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ArsM
-
-
-
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AS3MT
methylarsonite methyltransferase
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-
-
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S-adenosyl-L-methionine:arsenic(III) methyltransferase
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-
-
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S-adenosyl-L-methionine:methylarsonite As-methyltransferase
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-
-
-
REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
S-adenosyl-L-methionine + arsenite = S-adenosyl-L-homocysteine + methylarsonate
show the reaction diagram
reaction modelling, overview
REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
transfer of methyl group
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-
-
-
SYSTEMATIC NAME
IUBMB Comments
S-adenosyl-L-methionine:arsenous acid As-methyltransferase
An enzyme responsible for synthesis of trivalent methylarsenical antibiotics in microbes [11] or detoxification of inorganic arsenous acid in animals. The in vivo substrate is arsenic triglutathione or similar thiol (depending on the organism) [6], from which the arsenic is transferred to the enzyme forming bonds with the thiol groups of three cysteine residues [10] via a disulfide bond cascade pathway [7, 8]. Most of the substrates undergo two methylations and are converted to dimethylarsinous acid [9]. However, a small fraction are released earlier as methylarsonous acid, and a smaller amount proceeds via a third methylation, resulting in the volatile product trimethylarsane. Methylation involves temporary oxidation to arsenic(V) valency, followed by reduction back to arsenic(III) valency using electrons provided by thioredoxin or a similar reduction system. The arsenic(III) products are quickly oxidized in the presence of oxygen to the corresponding arsenic(V) species.
CAS REGISTRY NUMBER
COMMENTARY hide
167140-41-2
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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 + arsenite
S-adenosyl-L-homocysteine + methylarsonate
show the reaction diagram
-
-
-
?
S-adenosyl-L-methionine + methylarsonite
S-adenosyl-L-homocysteine + dimethylarsinate
show the reaction diagram
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-
-
?
S-adenosyl-L-methionine + arsenite
S-adenosyl-L-homocysteine + methylarsonate
show the reaction diagram
S-adenosyl-L-methionine + methylarsonite
S-adenosyl-L-homocysteine + dimethylarsinate
show the reaction diagram
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-
-
-
?
additional information
?
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NATURAL SUBSTRATE
NATURAL PRODUCT
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
additional information
?
-
COFACTOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
S-adenosyl-L-methionine
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INHIBITOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
dimethylselenoxide
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weak activator of recombinant As(III)-methyltransferase, weak inhibitor of arsenite methylation in hepatocytes
methylselenic acid
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Sodium selenite
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trimethylselenonium iodide
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weak activator of recombinant As(III)-methyltransferase, weak inhibitor of arsenite methylation in hepatocytes
ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
thioredoxin
activates formation of methyl arsenic, dimethyl arsenic, and trimethyl arsenic
dimethylselenoxide
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weak activator of recombinant As(III)-methyltransferase, weak inhibitor of arsenite methylation in hepatocytes
trimethylselenonium iodide
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weak activator of recombinant As(III)-methyltransferase, weak inhibitor of arsenite methylation in hepatocytes
Ki VALUE [mM]
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.0194
methylselenic acid
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-
0.0014
Sodium selenite
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SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
pH RANGE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
7.5 - 11
pH 7.5: about 40% of maximal activity, pH 11: about 35% of maximal activity
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY hide
GeneOntology No.
LITERATURE
SOURCE
UNIPROT
ENTRY NAME
ORGANISM
NO. OF AA
NO. OF TRANSM. HELICES
MOLECULAR WEIGHT[Da]
SOURCE
SEQUENCE
LOCALIZATION PREDICTION?
AS3MT_RAT
369
0
41056
Swiss-Prot
other Location (Reliability: 1)
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
42000
x * 42000, SDS-PAGE
SUBUNIT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
?
x * 42000, SDS-PAGE
PURIFICATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
native enzyme several thousandfold using pH-dependent fractionation, chromatofocusing, and S-adenosylhomocysteine-affinity chromatography, the purification of AS3MT from liver cytosol is dependent on the presence of 1 mM dithiothreitol and 5 mM GSH
CLONED (Commentary)
ORGANISM
UNIPROT
LITERATURE
gene arsM, DNA and amino acid sequence determination and analysis, sequence comparisons, phylogenetic analysis, genotype-phenotype correlations for arsenic methylation and AS3MT
creation of a clonal human UROtsa cell line (UROtsa/F35) that expresses rat AS3MT and, unlike the parent UROtsa cell line, methylates inorganic arsenite and methylarsenite
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expression of rat AS3MT in a simian virus 40 (SV40)-transformed human urothelial cell line confers the capacity to methylate inorganic arsenic on cells that otherwise do not express AS3MT and that have a null phenotype for iAs methylation
REF.
AUTHORS
TITLE
JOURNAL
VOL.
PAGES
YEAR
ORGANISM (UNIPROT)
PUBMED ID
SOURCE
Walton, F.S.; Waters, S.B.; Jolley, S.L.; LeCluyse, E.L.; Thomas, D.J.; Styblo, M.
Selenium compounds modulate the activity of recombinant rat AsIII-methyltransferase and the methylation of arsenite by rat and human hepatocytes
Chem. Res. Toxicol.
16
261-265
2003
Homo sapiens, Rattus norvegicus
Manually annotated by BRENDA team
Waters, S.B.; Devesa, V.; Fricke, M.W.; Creed, J.T.; Styblo, M.; Thomas, D.J.
Glutathione modulates recombinant rat arsenic (+3 oxidation state) methyltransferase-catalyzed formation of trimethylarsine oxide and trimethylarsine
Chem. Res. Toxicol.
17
1621-1629
2004
Rattus norvegicus (Q8VHT6)
Manually annotated by BRENDA team
Lin, S.; Shi, Q.; Nix, F.B.; Styblo, M.; Beck, M.A.; Herbin-Davis, K.M.; Hall, L.L.; Simeonsson, J.B.; Thomas, D.J.
A novel S-adenosyl-L-methionine:arsenic(III) methyltransferase from rat liver cytosol
J. Biol. Chem.
277
10795-10803
2002
Rattus norvegicus (Q8VHT6), Homo sapiens (Q9HBK9), Homo sapiens
Manually annotated by BRENDA team
Thomas, D.J.; Li, J.; Waters, S.B.; Xing, W.; Adair, B.M.; Drobna, Z.; Devesa, V.; Styblo, M.
Arsenic (+3 oxidation state) methyltransferase and the methylation of arsenicals
Exp. Biol. Med.
232
3-13
2007
Bos taurus, Bos taurus (Q58DQ0), Ciona intestinalis, Gallus gallus, Homo sapiens (Q9HBK9), Mus musculus, no activity in Caenorhabditis elegans, no activity in Drosophila melanogaster, Oncorhynchus mykiss, Pan troglodytes, Rattus norvegicus, Rattus norvegicus (Q8VHT6), Rhodopseudomonas palustris, Strongylocentrotus purpuratus
Manually annotated by BRENDA team
Drobna, Z.; Waters, S.B.; Devesa, V.; Harmon, A.W.; Thomas, D.J.; Styblo, M.
Metabolism and toxicity of arsenic in human urothelial cells expressing rat arsenic (+3 oxidation state)-methyltransferase
Toxicol. Appl. Pharmacol.
207
147-159
2005
Rattus norvegicus
Manually annotated by BRENDA team