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Information on EC 2.2.1.6 - acetolactate synthase and Organism(s) Bacillus subtilis and UniProt Accession P37251
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2.2.1.6 acetolactate synthaseIUBMB Comments
This enzyme requires thiamine diphosphate. The reaction shown is in the pathway of biosynthesis of valine; the enzyme can also transfer the acetaldehyde from pyruvate to 2-oxobutanoate, forming 2-ethyl-2-hydroxy-3-oxobutanoate, also known as 2-aceto-2-hydroxybutanoate, a reaction in the biosynthesis of isoleucine.
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Word Map
- 2.2.1.6
-
herbicide
-
weed
- sulfonylurea
-
als-inhibiting
-
branched-chain
- imidazolinone
-
biotype
-
cross-resistance
-
herbicide-resistant
- imazethapyr
- chlorsulfuron
- triazolopyrimidine
-
4.1.3.18
-
als-inhibitors
- glyphosate
-
target-site
- amaranthus
- imazamox
- acetoin
- sulfometuron
- 2,3-butanediol
- echinochloa
- protoporphyrinogen
-
broadleaf
- 2-ketobutyrate
-
non-target-site
-
whole-plant
- nicosulfuron
- accase
- hybridus
- rigidum
-
waterhemp
- mesotrione
-
postemergence
- crus-galli
-
safener
- 5-enolpyruvylshikimate-3-phosphate
-
ilvced
- alpha-ketobutyrate
- brewing
- rudis
- dicamba
- synthesis
- agriculture
- molecular biology
- glufosinate
-
thdp-dependent
- palmeri
- tuberculatus
- analysis
-
alopecurus
-
isomeroreductase
- pharmacology
-
herbicide-binding
- drug development
-
glyphosate-resistant
- kochia
- biotechnology
The taxonomic range for the selected organisms is: Bacillus subtilis
The enzyme appears in selected viruses and cellular organisms
The enzyme appears in selected viruses and cellular organisms
Synonyms
acetolactate synthase, acetohydroxy acid synthase, alpha-acetolactate synthase, ahas1, ahass, ahas2, ahas ii, acetohydroxy acid synthetase, acetohydroxy acid synthase i, ahas3, 
more
topSYNONYM 
ORGANISM
UNIPROT
COMMENTARY 
LITERATURE
acetohydroxy acid synthase
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-
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acetohydroxy acid synthetase
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-
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acetohydroxyacid synthase
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acetolactate pyruvate-lyase (carboxylating)
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acetolactate synthetase
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acetolactic synthetase
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-
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AHAS
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-
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alpha-acetohydroxy acid synthetase
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-
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alpha-acetohydroxyacid synthase
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-
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alpha-acetolactate synthase
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-
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alpha-acetolactate synthetase
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-
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alpha-ALS
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GST-mALS
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GST-wALS
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-
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synthase, acetolactate
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-
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REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
decarboxylation
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-
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C-C bond formation
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-
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PATHWAY SOURCE
PATHWAYS
KEGG
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-, -, -, -, -, -, -, -, -
SYSTEMATIC NAME
IUBMB Comments
pyruvate:pyruvate acetaldehydetransferase (decarboxylating)
This enzyme requires thiamine diphosphate. The reaction shown is in the pathway of biosynthesis of valine; the enzyme can also transfer the acetaldehyde from pyruvate to 2-oxobutanoate, forming 2-ethyl-2-hydroxy-3-oxobutanoate, also known as 2-aceto-2-hydroxybutanoate, a reaction in the biosynthesis of isoleucine.
CAS REGISTRY NUMBER
COMMENTARY
9027-45-6
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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
additional information
?
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-
enzyme additionallly displays 2-ketoisovalerate decarboxylase activity
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-
?
additional information
?
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enzyme additionallly displays 2-ketoisovalerate decarboxylase activity
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-
?
additional information
?
-
enzyme AlsS catalyzes the condensation of two pyruvate molecules to acetolactate with thiamine diphosphate and Mg2+ as cofactors. The enzyme also catalyzes the conversion of 2-ketoisovalerate into isobutyraldehyde, the immediate precursor of isobutanol
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-
?
additional information
?
-
-
enzyme AlsS catalyzes the condensation of two pyruvate molecules to acetolactate with thiamine diphosphate and Mg2+ as cofactors. The enzyme also catalyzes the conversion of 2-ketoisovalerate into isobutyraldehyde, the immediate precursor of isobutanol
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-
?
additional information
?
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acetolactate synthase AlsS is able to catalyze the decarboxylation of 2-oxoisovalerate both in vivo and in vitro
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?
additional information
?
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acetolactate synthase AlsS is able to catalyze the decarboxylation of 2-oxoisovalerate both in vivo and in vitro
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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
additional information
?
-
enzyme AlsS catalyzes the condensation of two pyruvate molecules to acetolactate with thiamine diphosphate and Mg2+ as cofactors. The enzyme also catalyzes the conversion of 2-ketoisovalerate into isobutyraldehyde, the immediate precursor of isobutanol
-
-
?
additional information
?
-
-
enzyme AlsS catalyzes the condensation of two pyruvate molecules to acetolactate with thiamine diphosphate and Mg2+ as cofactors. The enzyme also catalyzes the conversion of 2-ketoisovalerate into isobutyraldehyde, the immediate precursor of isobutanol
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-
?
COFACTOR
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
thiamine diphosphate
dependent on, the thiamine function of ThDP interacts with residues of one monomer and the adjacent monomer
METALS and IONS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
Mg2+
Mg2+
required, the Mg2+ cation is coordinated to residues of a single monomer, binding site structure, overview
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
SO42-
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competitive when assayed in phosphate buffer, mixed type, when assayed in acetate buffer
ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
TURNOVER NUMBER [1/s]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
kcat/KM VALUE [1/mMs-1]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
pH RANGE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
6 - 8
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pH 6.0: about 55% of maximal activity, pH 8.0: about 50% of maximal activity
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
TEMPERATURE RANGE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
ORGANISM
COMMENTARY
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
large subunit; wild-type strain MR168 and mutant strain JH642, gene ilvB
UniProt
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
evolution
the enzyme belongs to the ALS enzyme family that forms a distinct subgroup of ThDP-dependent enzymes. The ALS subfamily differs significantly in structure and possibly in catalytic mechanism, phylogenetic analysis. The ThDP-dependent enzymes cluster into three distinct sequence groups: acetolactate synthases, acetohydroxyacid synthases, and carboxylases. Eventhough ALS and AHAS catalyze the same reaction, they show different cofactors and domain structure: AHAS family enzymes have both catalytic and regulatory subunits, structure comparisons, overview
additional information
additional information
active site structure, catalytically relevant structure-function relationships, overview
additional information
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active site structure, catalytically relevant structure-function relationships, overview
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
SUBUNIT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
homotetramer
the enzyme is a homotetramer formed by dimers of dimers, each monomer is composed of three domains. The alpha-domain (up to N181) is connected by a random coil to the central beta-domain (P195 to A346). The C-terminal gamma-domain (from H376) is connected to the central beta-domain by an alpha-helix and a random coil linker, structure-function analysis of the enzyme, overview. The 12 C-terminal resolved residues of AlsS (D556-K567) fold into a short alpha-helix
CRYSTALLIZATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
purified enzyme in the presence of thiamine diphosphate and Mg2+, and in a transition state with a 2-lactyl moiety bound to thiamine diphosphate, X-ray diffraction structure determination and analysis at 2.3 A resolution, molecular replacement
sitting drop vapor diffusion method, using polyethylene glycol 300 (30%, w/v), CaAc (200 mM), and sodium cacodylate (100 mM, pH 6.5)
PROTEIN VARIANTS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
K176G
the naturally occuring mutation, substitution of two adenines to guanines in the ilvB gene, causes a cold-sensitive phenotype of mutant strain JH642. The acetolactate synthase efficiency in strain JH642 is reduced by 51fold
K40H
site-directed mutagenesis, the half-life of the mutant at 50°C is 44 h, compared to 81 h for the wild-type enzyme, the mutant enzyme shows reduced activity compared to the wild-type
K40I
K40Y
site-directed mutagenesis, the half-life of the mutant at 50°C is 110 h, compared to 81 h for the wild-type enzyme, the mutant enzyme shows reduced activity compared to the wild-type
P87A
site-directed mutagenesis, the half-life of the mutant at 50°C is 33 h, compared to 81 h for the wild-type enzyme, the mutant enzyme shows reduced activity compared to the wild-type
Q124S
site-directed mutagenesis, the half-life of the mutant at 50°C is 42 h, compared to 81 h for the wild-type enzyme, the mutant enzyme shows reduced activity compared to the wild-type
Q424S
site-directed mutagenesis, the half-life of the mutant at 50°C is 104 h, compared to 81 h for the wild-type enzyme, the mutant enzyme shows increased activity compared to the wild-type
Q424S/Q487S
site-directed mutagenesis, the half-life of the mutant at 50°C is 94 h, compared to 81 h for the wild-type enzyme, the mutant enzyme shows highly reduced activity compared to the wild-type
Q487A
Q487G
Q487I
Q487L
Q487S
T84V
site-directed mutagenesis, the half-life of the mutant at 50°C is 2.5 h, compared to 81 h for the wild-type enzyme, the mutant enzyme shows highly reduced activity compared to the wild-type
Y481A
site-directed mutagenesis, the half-life of the mutant at 50°C is 19 h, compared to 81 h for the wild-type enzyme, the mutant enzyme shows highly reduced activity compared to the wild-type
additional information
K40I
site-directed mutagenesis, the half-life of the mutant at 50°C is 89 h, compared to 81 h for the wild-type enzyme, the mutant enzyme shows highly reduced activity compared to the wild-type
K40I
the mutant shows slightly improved activity towards 2-oxoisovalerate compared to the wild type enzyme
Q487A
mutation diminishes decarboxylase activity but maintains the synthase activity
Q487A
wild-type additionally catalyzes the decarboxylation of 2-oxoisovalerate. Mutation diminishes only the decarboxylase activity but maintains the acetolactate synthase activity
Q487G
mutation diminishes decarboxylase activity but maintains the synthase activity
Q487G
wild-type additionally catalyzes the decarboxylation of 2-oxoisovalerate. Mutation diminishes only the decarboxylase activity but maintains the acetolactate synthase activity
Q487I
loss of acetolactate synthase activity, decrease in decarboxylase activity
Q487L
loss of acetolactate synthase activity, decrease in decarboxylase activity
Q487S
mutation diminishes decarboxylase activity but maintains the synthase activity
Q487S
site-directed mutagenesis, the half-life of the mutant at 50°C is 22 h, compared to 81 h for the wild-type enzyme, the mutant enzyme shows reduced activity compared to the wild-type
Q487S
wild-type additionally catalyzes the decarboxylation of 2-oxoisovalerate. Mutation diminishes only the decarboxylase activity but maintains the acetolactate synthase activity
additional information
structure-guided mutagenesis strategy to generate enzyme AlsS variants
additional information
-
structure-guided mutagenesis strategy to generate enzyme AlsS variants
TEMPERATURE STABILITY
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
50
half-life of recombinant C-terminally His-tagged enzyme is 81 h, comparison with half-lives of mutant enzymes, overview
50 - 60
at 50°C and 60°C, the enzyme shows a half-life of 81 h and 16 h, respectively
ORGANIC SOLVENT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
Ethanol
the enzyme retains 50% activity in the presence of 13% (v/v) ethanol
isobutanol
the enzyme retains 50% activity in the presence of 3% (v/v) isobutanol
n-Butanol
the enzyme retains 50% activity in the presence of 3% (v/v) n-butanol
PURIFICATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
Ni2+-NTA column chromatography, HiTrap Q column chromatography, and Superdex S200 gel filtration
recombinant C-terminally His-tagged wild-type and mutant enzymes from Escherichia coli
CLONED (Commentary)
ORGANISM
UNIPROT
LITERATURE
co-expression of acetolactate synthase and omega-transaminase in Escherichia coli
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expressed in Escherichia coli BL21(DE3) pLys Express and HMS174(DE3) cells
gene alsS, inducible overexpression in a constructed pta mutant strains RH35 and RH36 of Bacillus subtilis, the recombinant overexpression of the enzyme leads to increased acetolactate synthase activity and alteration of carbon flux into the acetoin biosynthesis pathway, alterations of involved enzyme activities, overview
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phylogenetic analysis, recombinant expression of wild-type and mutant C-terminally His-tagged enzymes in Escherichia coli
APPLICATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
synthesis
synthesis
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co-expression of acetolactate synthase and omega-transaminase in Escherichia coli as a whole-cell biocatalyst for production of (S)-alpha-benzylamine. Product (S)-alpha-benzylamine can be moved into the extraction solution via an organic solvent
synthesis
Bacillus subtilis acetolactate synthase can act as key biocatalyst in the formation of isobutanol which is deemed to be a next-generation biofuel and a renewable platform chemical. The enzyme AlsS catalyzes the conversion of 2-ketoisovalerate into isobutyraldehyde, the immediate precursor of isobutanol
REF.
AUTHORS
TITLE
JOURNAL
VOL.
PAGES
YEAR
ORGANISM (UNIPROT)
PUBMED ID
SOURCE
Holtzclaw, W.D.; Chapman, L.F
Degradative acetolactate synthase of Bacillus subtilis: purification and properties
J. Bacteriol.
121
917-922
1975
Bacillus subtilis
Zhu, Y.; Chen, X.; Chen, T.; Zhao, X.
Enhancement of riboflavin production by overexpression of acetolactate synthase in a pta mutant of Bacillus subtilis
FEMS Microbiol. Lett.
266
224-230
2007
Bacillus subtilis, Bacillus subtilis RH33::[pRB63]n
Atsumi, S.; Li, Z.; Liao, J.C.
Acetolactate synthase from Bacillus subtilis serves as a 2-ketoisovalerate decarboxylase for isobutanol biosynthesis in Escherichia coli
Appl. Environ. Microbiol.
75
6306-6311
2009
Bacillus subtilis, Bacillus subtilis (Q04789), Bacillus subtilis 168 (Q04789)
Yun, H.; Kim, B.G.
Asymmetric synthesis of (S)-alpha-methylbenzylamine by recombinant Escherichia coli co-expressing omega-transaminase and acetolactate synthase
Biosci. Biotechnol. Biochem.
72
3030-3033
2008
Bacillus subtilis
Wiegeshoff, F.; Marahiel, M.A.
Characterization of a mutation in the acetolactate synthase of Bacillus subtilis that causes a cold-sensitive phenotype
FEMS Microbiol. Lett.
272
30-34
2007
Bacillus subtilis (P37251), Bacillus subtilis
Sommer, B.; von Moeller, H.; Haack, M.; Qoura, F.; Langner, C.; Bourenkov, G.; Garbe, D.; Loll, B.; Brueck, T.
Detailed structure-function correlations of Bacillus subtilis acetolactate synthase
ChemBioChem
16
110-118
2015
Bacillus subtilis (Q04789), Bacillus subtilis, Bacillus subtilis PY79 (Q04789)
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