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Information on EC 2.1.1.246 - [methyl-Co(III) methanol-specific corrinoid protein]:coenzyme M methyltransferase and Organism(s) Methanosarcina barkeri and UniProt Accession O30640
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2.1.1.246 [methyl-Co(III) methanol-specific corrinoid protein]:coenzyme M methyltransferaseIUBMB Comments
The enzyme, which is involved in methanogenesis from methanol, catalyses the transfer of a methyl group from a corrinoid protein (see EC 2.1.1.90, methanol---corrinoid protein Co-methyltransferase), where it is bound to the cobalt cofactor, to CoM, forming the substrate for EC 2.8.4.1, coenzyme-B sulfoethylthiotransferase, the enzyme that catalyses the final step in methanogenesis. Free methylcob(I)alamin can substitute for the corrinoid protein in vitro .
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Word Map
- 2.1.1.246
- methyltransferases
-
euchromatic
- methanosarcina
- barkeri
-
rna-directed
-
methanogenesis
- monomethylamine
-
24-nucleotide
- dimethylamine
- biofuel production
- synthesis
The taxonomic range for the selected organisms is: Methanosarcina barkeri
The expected taxonomic range for this enzyme is: Bacteria, Archaea
The expected taxonomic range for this enzyme is: Bacteria, Archaea
Reaction Schemes
+
=
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a [methyl-Co(III) methanol-specific corrinoid protein]
+
=
+
a [Co(I) methanol-specific corrinoid protein]
Synonyms
methyltransferase 2, mt2-a, mt2-m, methylcobalamin:coenzyme m methyltransferase, methylcobamide:com methyltransferase, methanol-specific methyltransferase 2, methylcobamide:coenzyme m methyltransferase, co-methyl-5-hydroxybenzimidazolylcobamide:2-mercapto-ethanesulphonic acid methyltransferase, 
more
topSYNONYM 
ORGANISM
UNIPROT
COMMENTARY 
LITERATURE
mtaA
mtaA
-
-
-
-
REACTION
REACTION DIAGRAM
COMMENTARY
ORGANISM
UNIPROT
LITERATURE
a [methyl-Co(III) methanol-specific corrinoid protein] + CoM = methyl-CoM + a [Co(I) methanol-specific corrinoid protein]
coenzyme M binds with its thiol group to the zinc in the active site of MtaA forming a coenzyme M thiolate zinc complex
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SYSTEMATIC NAME
IUBMB Comments
methylated methanol-specific corrinoid protein:coenzyme M methyltransferase
The enzyme, which is involved in methanogenesis from methanol, catalyses the transfer of a methyl group from a corrinoid protein (see EC 2.1.1.90, methanol---corrinoid protein Co-methyltransferase), where it is bound to the cobalt cofactor, to CoM, forming the substrate for EC 2.8.4.1, coenzyme-B sulfoethylthiotransferase, the enzyme that catalyses the final step in methanogenesis. Free methylcob(I)alamin can substitute for the corrinoid protein in vitro [5].
CAS REGISTRY NUMBER
COMMENTARY
53414-88-3
methylcobalamin-coenzyme M methyltransferase, EC 2.1.1.246 to EC 2.1.1.253
SUBSTRATE
PRODUCT
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
(Substrate)
LITERATURE
(Substrate)
(Substrate)
COMMENTARY
(Product)
(Product)
LITERATURE
(Product)
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
r=reversible
ir=irreversible
?=not specified
a [methyl-Co(III) methanol-specific corrinoid protein] + 3-mercaptopropanoic acid
methyl-3-mercaptopropanoic acid + a [Co(I) methanol-specific corrinoid protein]
-
-
-
r
a [methyl-Co(III) methanol-specific corrinoid protein] + coenzyme M
methyl-CoM + a [Co(I) methanol-specific corrinoid protein]
a [methyl-Co(III) methanol-specific corrinoid protein] + coenzyme M
methyl-CoM + a [Co(I) methanol-specific corrinoid protein]
a [methyl-Co(III) methanol-specific corrinoid protein] + CoM
methyl-CoM + a [Co(I) methanol-specific corrinoid protein]
-
-
-
?, r
a [methyl-Co(III) methanol-specific corrinoid protein] + coenzyme M
methyl-CoM + a [Co(I) methanol-specific corrinoid protein]
-
-
-
r
a [methyl-Co(III) methanol-specific corrinoid protein] + coenzyme M
methyl-CoM + a [Co(I) methanol-specific corrinoid protein]
the enzyme methylcobamide:CoM methyltransferase, MT2, catalyzes the transfer of the methyl group from the MT1-bound methylcobamide prosthetic group to coenzyme M
-
-
r
a [methyl-Co(III) methanol-specific corrinoid protein] + coenzyme M
methyl-CoM + a [Co(I) methanol-specific corrinoid protein]
-
-
-
-
?
a [methyl-Co(III) methanol-specific corrinoid protein] + coenzyme M
methyl-CoM + a [Co(I) methanol-specific corrinoid protein]
-
-
-
-
r
additional information
?
-
conversions of monomethylamine and dimethylamine to CH3-SCoM are dependent upon MT2-A, and are not supported by MT2-M. In contrast, MT2-M acts specifically in metabolism of methanol, but does not substitute for MT2-A in conversion of monomethylamine or dimethylamine. Nevertheless, both isozymes are capable of supporting the conversion of trimethylamine
-
-
?
additional information
?
-
-
conversions of monomethylamine and dimethylamine to CH3-SCoM are dependent upon MT2-A, and are not supported by MT2-M. In contrast, MT2-M acts specifically in metabolism of methanol, but does not substitute for MT2-A in conversion of monomethylamine or dimethylamine. Nevertheless, both isozymes are capable of supporting the conversion of trimethylamine
-
-
?
additional information
?
-
-
transferase MtaA catalyzes the transfer of the methyl group from methylated transferase MtaBC to coenzyme M. Instead of methylated transferase MtaBC, MtaA can also use free methylcobalamin as the methyl donor. MtaA activates coenzyme M for nucleophilic attack of the methyl group of the methylcobamide
-
-
?
additional information
?
-
-
in the assay for methanol:coenzyme M methyltransferase activity cob(I)alamin can be substituted by cob(I)inamide which is devoid of the nucleotide loopmethylation of cob(I)inamide with methanol is dependent on imidazole but not on the demethylation of methylcob(III)inamide with coenzyme M
-
-
?
additional information
?
-
-
recombinant MtaA catalyzes the formation of methyl-coenzyme M from free CH3-cob(III)alamin and coenzyme M at specific rates comparable to those predicted for MtaA-catalyzed MtaC demethylation
-
-
?
additional information
?
-
the reaction for possible production of methanol from the anaerobic oxidation of methane can be reversed in vitro. Develoment of an in vitro functional assay that demonstrates MtaABC can catalyze the energetically unfavorable reverse reaction starting from methyl coenzyme M and generating methanol as a product, overview. MtaABC enzyme protein complex to catalyze the methyl transfer from methanol to CoM to form methyl-CoM, which is energetically favorable in the forward reaction. MtaB catalyzes a methyl transfer from methanol to the corrinoid cofactor of the MtaC subunit. MtaA then catalyzes the transfer of the methyl group to CoM to form methyl-CoM. DTNB assays for the forward and reverse MtaABC reactions. Methylcobalamin assay of purified recombinant MtaA.Demethylation of methylcobalamin in a CoM-dependent manner by MtaA
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-
-
NATURAL SUBSTRATE
NATURAL PRODUCT
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
(Substrate)
LITERATURE
(Substrate)
(Substrate)
COMMENTARY
(Product)
(Product)
LITERATURE
(Product)
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
r=reversible
ir=irreversible
?=not specified
a [methyl-Co(III) methanol-specific corrinoid protein] + coenzyme M
methyl-CoM + a [Co(I) methanol-specific corrinoid protein]
-
-
-
r
a [methyl-Co(III) methanol-specific corrinoid protein] + coenzyme M
methyl-CoM + a [Co(I) methanol-specific corrinoid protein]
a [methyl-Co(III) methanol-specific corrinoid protein] + CoM
methyl-CoM + a [Co(I) methanol-specific corrinoid protein]
-
-
-
?
a [methyl-Co(III) methanol-specific corrinoid protein] + coenzyme M
methyl-CoM + a [Co(I) methanol-specific corrinoid protein]
-
-
-
-
?
a [methyl-Co(III) methanol-specific corrinoid protein] + coenzyme M
methyl-CoM + a [Co(I) methanol-specific corrinoid protein]
-
-
-
-
r
additional information
?
-
conversions of monomethylamine and dimethylamine to CH3-SCoM are dependent upon MT2-A, and are not supported by MT2-M. In contrast, MT2-M acts specifically in metabolism of methanol, but does not substitute for MT2-A in conversion of monomethylamine or dimethylamine. Nevertheless, both isozymes are capable of supporting the conversion of trimethylamine
-
-
?
additional information
?
-
-
conversions of monomethylamine and dimethylamine to CH3-SCoM are dependent upon MT2-A, and are not supported by MT2-M. In contrast, MT2-M acts specifically in metabolism of methanol, but does not substitute for MT2-A in conversion of monomethylamine or dimethylamine. Nevertheless, both isozymes are capable of supporting the conversion of trimethylamine
-
-
?
additional information
?
-
-
transferase MtaA catalyzes the transfer of the methyl group from methylated transferase MtaBC to coenzyme M. Instead of methylated transferase MtaBC, MtaA can also use free methylcobalamin as the methyl donor. MtaA activates coenzyme M for nucleophilic attack of the methyl group of the methylcobamide
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-
?
METALS and IONS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
Co2+
Zn2+
additional information
-
Zn21 or Co21 are required for MtaA activity, Zn2+ can be replaced by Co2+ but not by Mg2+, the kinetics of activation by Co2+ being similarily slow. About 1 mol of transition metal is bound per mol of protein. The role of the transition metal in MtaA is to lower the microscopic pKa of the thiol group of coenzyme M by coordination to the zinc, and thus to increase its nucleophilicity for methyl group attack, pKZn2+ of MtaA is over 15
Co2+
-
required, the apoprotein reacts with zinc or cobalt to the fully active holoenzyme
Zn2+
-
1 mol per mol of enzyme, required, the apoprotein reacts with zinc or cobalt to the fully active holoenzyme
Zn2+
-
dependent on, wild-type MtaA has a zinc content of 0.91 mol/mol, binding structure, overview
Zn2+
-
Mta contains 1 mol Zn2+ per mol of enzyme, Zn2+ can be substituted by Co2+
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
EDTA
-
75% inhibition at 1 mM, complete inhibition at 2 mM, reversible by Zn2+ addition, competitive versus Zn2+, kinetics, overview
imidazole
-
the demethylation of cob(I)inamide reaction is inhibited by imidazole. Imidazole does not inhibit methyltransfer from methylcob(III)alamin to coenzyme M at 10 mM
additional information
-
1 mm nitrilotriacetic acid has almost no effect on the MtaA activity
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ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
methanol
-
MtaB plus methanol positively affect the catalytic efficiency of MtaA. activation of MtaA by MtaB is methanol-dependent. Methylation of cob(I)inamide with methanol is dependent on imidazole but not on the demethylation of methylcob(III)inamide with coenzyme M. The demethylation reaction is even inhibited by imidazole
MtaB
-
MtaB plus methanol positively affect the catalytic efficiency of MtaA. activation of MtaA by MtaB is methanol-dependent. Methylation of cob(I)inamide with methanol is dependent on imidazole but not on the demethylation of methylcob(III)inamide with coenzyme M. The demethylation reaction is even inhibited by imidazole
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Ti(III) citrate
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increases the specific activity of MtaA by 60% and decreases the apparent Km for methylcob(III)-alamin from 0.003 mM to below 0.001 mM
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
additional information
additional information
steady-state kinetics of isozymes MT2-A and MT2-M, overview
-
additional information
additional information
-
steady-state kinetics of isozymes MT2-A and MT2-M, overview
-
additional information
additional information
-
MtaA kinetics, overview. Demethylation of methylcob(III)alamin catalysed by MtaA alone exhibit apparent Km for cob(I)alamin and methylcob(III)alamin of above 1 mm
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SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
0.154
MT2 activity in recombinant Escherichia coli cells transfected with gene cmtM, pH 7.2, 37°C
1.21
MT2 activity in recombinant Escherichia coli cells transfected with gene cmtA, pH 7.2, 37°C
2.2
MT2 activity in cells grown on trimethylamine, pH 7.2, 37°C
8
-
MtaA with substrate methylcob(III)inamide, 50 mM methylcob(III)inamide as substrate show an activity of 8 U/mg, approximately 40fold higher than with 50 mM methylcob(III)-alamin, pH 7.0, 37°C
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
7.2
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
ORGANISM
COMMENTARY
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
isozymes MT2-A and MT2-M encoded by genes cmtA and cmtM
UniProt
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
SOURCE
the isozymes MT2-A and MT2-M are differentially expressed depending upon the substrate available for growth
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
evolution
-
Methanosarcina barkeri contains an isoenzyme of MtaA designated MtbA. The isoenzyme reacts with MtaC with only 2.5% of the activity of MtaA
metabolism
physiological function
additional information
metabolism
-
methyl-coenzyme M formation from coenzyme M and methanol in Methanosarcina barkeri is catalysed by an enzyme system composed of three polypeptides MtaA, MtaB and MtaC, the latter of which harbours a corrinoid prosthetic group. We report here that MtaC can be substituted by free cob(I)alamin which is methylated with methanol in an MtaB-catalysed reaction and demethylated with coenzyme M in an MtaA-catalysed reaction
metabolism
-
the enzyme system catalyzing the formation of methyl-coenzyme M from methanol and coenzyme M in Methanosarcina barkeri is composed of the three different polypeptides MtaA, MtaB and MtaC of which MtaC harbors a corrinoid prosthetic group
metabolism
-
the enzyme system from Methanosarcina barkeri is composed of two methyltransferases, transferase MT1, which is composed of a 50-kDa subunit, MtaB, and a 27-kDa corrinoid-harbouring subunit, MtaC, catalyzes the methylation of free cob(1)alamin with methanol, EC 2.1.1.90, and transferase MT2 catalyzes the transfer of the methyl group from CH,-MT1 to coenzyme M. Instead of CH,-MTI, MtaA can also use free methylcobalamin as the methyl donor. MtaC with its supernucleophilic cobamide prosthetic group accepts the methyl group from methanol and passes it to coenzyme M, MtaB activates methanol for nucleophilic attack by the cob(1)amide, and MtaA activates coenzyme M for nucleophilic attack of the methyl group of the methylcobamide
physiological function
-
a positive effect of MtaA on the catalytic efficiency of MtaB is specific for MtaA. In the absence of MtaA no effect is observed, while in the presence of MtaA the formation of methylcob(III)alamin from methanol and cob(I)alamin is apparently inhibited by coenzyme M, probably because under these conditions MtaA actively catalyses the demethylation of methylcob(III)alamin. MtaB plus methanol positively affect the catalytic efficiency of MtaA
physiological function
-
the methyltransferase designated MtaA together with the proteins MtaB and MtaC mediate the formation of methyl-coenzyme M from methanol and coenzyme M. MtaC is a 28-kDa corrinoid protein, MtaB, EC 2.1.1.90, catalyzes the methylation of MtaC and MtaA catalyzes the demethylation of methylated MtaC
physiological function
methanol:coenzyme M methyltransferase is an enzyme complex composed of three subunits, MtaA, MtaB, and MtaC, found in methanogenic archaea and is needed for their growth on methanol ultimately producing methane. MtaABC catalyzes the energetically favorable methyl transfer from methanol to coenzyme M to form methyl coenzyme M, an important reaction for possible production of methanol from the anaerobic oxidation of methane
additional information
-
MtaC and MtaB form a tight complex and the encoding genes form a transcription unit, whereas MtaA purifies separately and its encoding gene is located separately
additional information
-
the enzyme system catalyzing the formation of methyl-coenzyme M from methanol and coenzyme M in Methanosarcina barkeri is composed of the three different polypeptides MtaA, MtaB and MtaC of which MtaC harbors a corrinoid prosthetic group
additional information
enzyme complex structure analysis and structure-function analysis, overview
UNIPROT
ENTRY NAME
ORGANISM
NO. OF AA
NO. OF TRANSM. HELICES
MOLECULAR WEIGHT[Da]
SOURCE
SEQUENCE
LOCALIZATION PREDICTION
The reliability class of the localization prediction ranges from 1 (very reliable) to 5 (not reliable).
The reliability class of the localization prediction ranges from 1 (very reliable) to 5 (not reliable). MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
34000
x * 34000, isozymes MT2-A and MT2-M, SDS-PAGE, x * 36700, about, isozyme MT2-A, sequence calculation
36700
x * 34000, isozymes MT2-A and MT2-M, SDS-PAGE, x * 36700, about, isozyme MT2-A, sequence calculation
SUBUNIT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
?
x * 34000, isozymes MT2-A and MT2-M, SDS-PAGE, x * 36700, about, isozyme MT2-A, sequence calculation
additional information
additional information
the isozymes MT2-A and MT2-M differ in their overall charge
additional information
-
the isozymes MT2-A and MT2-M differ in their overall charge
PROTEIN VARIANTS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
C239A
-
site-directed mutagenesis, mutation of the residue involved in zinc coordination in MtaA results in reduced zinc content and reduced activity compared to the wild-type enzyme
H237A
-
site-directed mutagenesis, mutation of the residue involved in zinc coordination in MtaA results in reduced zinc content and reduced activity compared to the wild-type enzyme
PURIFICATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
recombinant His-tagged apo MtaA from Escherichia coli strain M15 by nickel affinity and anionexchange chromatography
-
recombinant His-tagged MtaA from Escherichia coli by nickel affinity chromatography, dialysis, and anion exchange chromatography
recombinant His-tagged MtaA from Escherichia coli strain M15 by nickel affinity and anion exchange chromatography to homogeneity
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recombinant His6-tagged MtaA from Escherichia coli strain M15 to homogeneity by nickel affinity and anion exchange chromatography
-
recombinant N-terminally His-tagged isozymes MtaA and MtbA from Escherichia coli strain M15 by nickel affinity chromatography
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CLONED (Commentary)
ORGANISM
UNIPROT
LITERATURE
genes cmtA and cmtM, DNA and amino acid sequence determination and analysis, expressionin Escherichia coli strain XL-1 Blue
gene mtaA, DNA and amino acid sequence determination and analysis, gene mtaA is monocislronically transcribed, transcription of the gene is positively controlled by the growth substrate rnethanol, overexpression of the His6-tagged enzyme in Escherichia coli strain M15
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gene mtaA, expression of His-tagged MtaA in Escherichia coli strain M15
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gene mtaA, recombinant expression as enzyme complex Methanosarcina barkeri MtaABC in Escherichia coli, recombinant expression of His-tagged MtaA in Escherichia coli
gene mtaA, sequence comparison, expression of His-tagged MtaA in Escherichia coli strain M15
-
genes mtaA and mtaB, expression of N-terminally His-tagged isozymes MtaA and MtbA in Escherichia coli strain M15
-
overexpression of His-tagged inactive MtaA apoprotein in Escherichia coli strain M15 grown in the presence of 2 mM EDTA
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EXPRESSION
ORGANISM
UNIPROT
LITERATURE
APPLICATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
biofuel production
demonstration of an in vitro ability of MtaABC to produce methanol may ultimately enable the anaerobic oxidation of methane to produce methanol and from methanol alternative fuel or fuel-precursor molecules
synthesis
in vitro methanol production from methyl coenzyme M using the Methanosarcina barkeri MtaABC protein complex
REF.
AUTHORS
TITLE
JOURNAL
VOL.
PAGES
YEAR
ORGANISM (UNIPROT)
PUBMED ID
SOURCE
Sauer, K.; Thauer, R.K.
Methanol:coenzyme M methyltransferase from Methanosarcina barkeri. Zinc dependence and thermodynamics of the methanol:cob(I)alamin methyltransferase reaction
Eur. J. Biochem.
249
280-285
1997
Methanosarcina barkeri
Harms, U.; Thauer, R.
Methylcobalamin:coenzyme M methyltransferase isoenzymes MtaA and MtbA from Methanosarcina barkeri: Cloning, sequencing and differential transcription of the encoding genes, and functional overexpression of the mtaA gene in Escherichia coli
Eur. J. Biochem.
235
653-659
1996
Methanosarcina barkeri, Methanosarcina barkeri DSM 804
Sauer, K.; Thauer, R.K.
Methanol:coenzyme M methyltransferase from Methanosarcina barkeri - identification of the active-site histidine in the corrinoid-harboring subunit MtaC by site-directed mutagenesis
Eur. J. Biochem.
253
698-705
1998
Methanosarcina barkeri
Sauer, K.; Thauer, R.K.
Methanol:coenzyme M methyltransferase from Methanosarcina barkeri - substitution of the corrinoid harbouring subunit MtaC by free cob(I)alamin
Eur. J. Biochem.
261
674-681
1999
Methanosarcina barkeri
Sauer, K.; Thauer, R.K.
Methyl-coenzyme M formation in methanogenic archaea. Involvement of zinc in coenzyme M activation
Eur. J. Biochem.
267
2498-2504
2000
Methanosarcina barkeri
Krer, M.; Haumann, M.; Meyer-Klaucke, W.; Thauer, R.; Dau, H.
The role of zinc in the methylation of the coenzyme M thiol group in methanol:coenzyme M methyltransferase from Methanosarcina barkeri: new insights from X-ray absorption spectroscopy
Eur. J. Biochem.
269
2117-2123
2002
Methanosarcina barkeri, Methanosarcina barkeri Fusaro / DSM 804
LeClerc, G.M.; Grahame, D.A.
Methylcobamide:coenzyme M methyltransferase isozymes from Methanosarcina barkeri. Physicochemical characterization, cloning, sequence analysis, and heterologous gene expression
J. Biol. Chem.
271
18725-18731
1996
Methanosarcina barkeri (O30640), Methanosarcina barkeri
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