Information on EC 4.2.1.112 - acetylene hydratase

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The expected taxonomic range for this enzyme is: Bacteria

EC NUMBER
COMMENTARY hide
4.2.1.112
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RECOMMENDED NAME
GeneOntology No.
acetylene hydratase
REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
acetaldehyde = acetylene + H2O
show the reaction diagram
PATHWAY
BRENDA Link
KEGG Link
MetaCyc Link
acetylene degradation
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Chloroalkane and chloroalkene degradation
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Microbial metabolism in diverse environments
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SYSTEMATIC NAME
IUBMB Comments
acetaldehyde hydro-lyase (acetylene-forming)
This is a non-redox-active enzyme that contains two molybdopterin guanine dinucleotide (MGD) cofactors, a tungsten centre and a cubane type [4Fe-4S] cluster [2].The tungsten centre binds a water molecule that is activated by an adjacent aspartate residue, enabling it to attack acetylene bound in a distinct hydrophobic pocket [2]. Ethylene cannot act as a substrate [1].
CAS REGISTRY NUMBER
COMMENTARY hide
75788-81-7
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ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
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Manually annotated by BRENDA team
isolated from soil, aerobic strain
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Manually annotated by BRENDA team
Gordonia sp. aerobic
isolated from soil, aerobic strain
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Manually annotated by BRENDA team
two aerobic isolates from soil, DSM 44186 and 44188
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Manually annotated by BRENDA team
isolated from soil, aerobic strain
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Manually annotated by BRENDA team
isolated from soil, aerobic strain
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Manually annotated by BRENDA team
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
metabolism
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in isoprenoid biosynthesis, the protein (E)-4-hydroxy-3-methyl-but-2-enyl diphosphate reductase performs a 2H+/2e- reduction and deoxygenation of (E)-4-hydroxy-3-methyl-but-2-enyl diphosphate, yielding isopentenyl diphosphate and dimethylallyl diphosphate. In addition to its role as a 2H+/2e- reductase in isoprenoid biosynthesis, IspH can catalyse a second class of reactions: the addition of water to acetylene groups to produce aldehyde and ketone products
additional information
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study of the chemoselectivity of tungsten-dependent acetylene hydratase, overview
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
acetylene + H2O
acetaldehyde
show the reaction diagram
but-3-ynyl diphosphate
4-oxobutyl diphosphate
show the reaction diagram
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via (E)-4-hydroxybut-3-enyl diphosphate
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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
acetylene + H2O
acetaldehyde
show the reaction diagram
COFACTOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
molybdenum cofactor
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molybdopterin cofactor, 0.94 mol per mol of enzyme in purified recombinant enzyme
molybdopterin guanine dinucleotide
METALS and IONS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
Iron-sulfur cluster
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dependent on, the enzyme is a tungsten/iron-sulfur protein, 4.8 mol of iron per mol of enzyme and 3.9 mol od acid-labile sulfur per mol of enzyme
Molybdenum
Ti(III)citrate
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a strong reductant is absolutely required for activity
Tungsten
additional information
INHIBITORS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
but-3-ynyl diphosphate
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CO
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90% inhibition at 0.8 mM
HgCl2
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reduces enzyme activity by 40% at 0.01 mM, 80% at 0.1 mM, and 98% at 0.2 mM
KCN
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20% inhibition at 1 mM, 40% inhibition at 5-10 mM
nitric oxide
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complete inhibition at 3 mM
pent-4-ynyl diphosphate
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propyne
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competitive inhibitor
propynyl diphosphate
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additional information
ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
Dithionite
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a strong reductant is required for activity
Ti(III)citrate
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a strong reductant is required for activity
additional information
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.014
Acetylene
additional information
additional information
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
10.7
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purified native enzyme
13
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crude cell extract of cells grown in presence of acetylene
14.2
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purified recombinant enzyme, pH 7.5, 30C
26.5
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purified native enzyme
69.2
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purified enzyme
additional information
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
pH RANGE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
TEMPERATURE RANGE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
pI VALUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
4.3
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chromatofocusing
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE
additional information
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY hide
GeneOntology No.
LITERATURE
SOURCE
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
60000
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gel filtration
83550
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MALDI mass spectrometry
85000
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mass spectrometry
SUBUNITS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
monomer
additional information
Crystallization/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
the enzyme complexed with the aldehyde 4-oxobutyl diphosphate, X-ray diffraction structure determination and anaysis at 1.8 A resolution
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purified enzyme, the mother liquor contains plus 15% (v/v) 2-methyl-2,5-pentanediol, X-ray diffraction structure determination and analysis at 1.26-1.95 A resolution, modeling
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purified native enzyme, sitting drop vapour diffusion method in a 95%N2/5%H2 atmosphere, 10 mg/ml protein in 5 mM HEPES-NaOH, pH 7.5, and 3 mM dithionite or Ti(III)citrate, mixing with an equal volume of 0.002 ml of precipitant solution equilibrated against 0.3 ml of reservoir, 20C, 3 weeks, X-ray diffraction structure determination and analysis at 2.3 A resolution, molecular replacement
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purified recombinant NarG-fusion acetylene hydratase, sitting and hanging drop vapor diffusion methods, small crystals after 3 to 4 weeks, 6.5-10 mg/ml protein in solution containing 5 mM HEPES-NaOH, pH 7.5, and 7.5 mM Na2S2O4, cryoprotection by 20% v/v 2-methyl-2,4-pentanediol, X-ray diffraction structure determination and analysis
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OXIDATION STABILITY
ORGANISM
UNIPROT
LITERATURE
the enzyme is oxygen-sensitive
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667090, 668453
STORAGE STABILITY
ORGANISM
UNIPROT
LITERATURE
enzyme activity is stable even after prolonged storage of the cell extract or of the purified protein under air
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Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
native enzyme 29.7fold by ammonium sulfate fractionation, ion exchange chromatography, and gel filtration to homogeneity
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native enzyme 7.6fold by ammonium sulfate fractionation, ion exchange chromatography, and gel filtration to homogeneity
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under air at room temperature, native enzyme 240-fold by ammonium sulfate fractionation, anion exchange chromatography, gel filtration, and a second anion exchange chromatography step to homogeneity
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Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
cloning of AH gene in Escherichia coli strain JM109, expression of wild-type enzyme, active-site variants of the enzyme, and of the nitrate reductase N-terminal chaperone binding site NarG-fusion enzyme in Escherichia coli strain BL21(DE3)
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ENGINEERING
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
D13E
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site-directed mutagenesis, almost inactive mutant
I142A
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site-directed mutagenesis, the mutant shows a marked loss of activity compared to the wild-type enzyme
K48A
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site-directed mutagenesis, the mutant shows unaltered activity compared to the wild-type enzyme
D13E
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site-directed mutagenesis, almost inactive mutant
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I142A
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site-directed mutagenesis, the mutant shows a marked loss of activity compared to the wild-type enzyme
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K48A
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site-directed mutagenesis, the mutant shows unaltered activity compared to the wild-type enzyme
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additional information