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Information on EC 2.2.1.6 - acetolactate synthase and Organism(s) Pseudomonas aeruginosa
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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: Pseudomonas aeruginosa
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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acetohydroxy acid synthetase
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-
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acetohydroxyacid synthase
acetolactate pyruvate-lyase (carboxylating)
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acetolactate synthetase
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-
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acetolactic synthetase
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AHAS
alpha-acetohydroxy acid synthetase
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alpha-acetohydroxyacid synthase
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alpha-acetolactate synthase
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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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-
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GST-wALS
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-
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synthase, acetolactate
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-
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acetohydroxyacid synthase
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AHAS
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REACTION
REACTION DIAGRAM
COMMENTARY
ORGANISM
UNIPROT
LITERATURE
2 pyruvate = 2-acetolactate + CO2
catalytic mechanism, detailed overview
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REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
C-C bond formation
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decarboxylation
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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
2 pyruvate
2-acetolactate + CO2
-
irreversible decarboxylation of pyruvate
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-
ir
pyruvate + 2-oxobutyrate
2-aceto-2-hydroxybutyrate + CO2
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irreversible decarboxylation of pyruvate
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-
ir
additional information
?
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the product of this enzyme-catalyzed reaction is either 2-acetolactate or 2-aceto-2-hydroxybutyrate obtained from self-condensation of pyruvate or condensation of puruvate and 2-ketobutyrate, respectively
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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
2 pyruvate
2-acetolactate + CO2
-
irreversible decarboxylation of pyruvate
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-
ir
pyruvate + 2-oxobutyrate
2-aceto-2-hydroxybutyrate + CO2
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irreversible decarboxylation of pyruvate
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-
ir
COFACTOR
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
FAD
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the anabolic enzyme form is dependent on the presence of FAD, structure of the enamine-FAD adduct
thiamine diphosphate
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dependent on, upon removal of the cofactor, the activity of the enzyme is completely abolished and again restored by readdition of thiamine diphosphate. ThDP has a central role in the enzymes catalytic mechanism. In the active site of enzyme, it is located at its centre with a unique V-conformation at the dimer interface. Decarboxylation of pyruvate is carried out by ThDP
METALS and IONS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
Mg2+
additional information
-
enzyme AHAS is not specific as far as metal ions are concerned. It is active in presence of any metal ion like Mn2+, Mg2+, Ca2+, Cd2+
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
additional information
-
feedback inhibition takes place in the holoenzyme containing the regulatory and the catalytic subunits. The branched-chain amino acids are believed to bind only to the regulatory subunit and inhibit the enzyme
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SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
ORGANISM
COMMENTARY
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
evolution
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three types of isozymes, AHAS I, II, III, are found in Enterobacteria encoded by ilvBN, ilvGMEDA, ilvIH operons, respectively. Bacterial AHAS consists of a regulatory and a catalytic subunit
malfunction
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enzyme inhibition abolishes biosynthesis of brachend chain amino acids and leads to bacteriostasis
metabolism
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the bacterial anabolic enzyme form catalyzes the first step in biosynthesis of branched amino acids isoleucine, leucine and valine. It catalyzes the first and the most crucial step which is either the self condensation of pyruvate to form 2-acetolactate or the condensation between lactate and 2-oxobutyrate to form 2-aceto-2-hydroxybutyrate. 2-acetolactate and 2-aceto-2-hydroxybutyrate serve as the precursors for the synthesis of leucine and valine while latter serves as the precursor for the synthesis of isoleucine. In some bacteria, the enzyme is responsible for the formation of butanediol and other products of fermentation
additional information
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there exist two types of the enzyme, catabolic and anabolic AHAS. The anabolic form of the enzyme consists of two subunits out of which one is catalytic while the other is regulatory in nature. The regulatory subunit acts via feedback inhibition
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
SUBUNIT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
tetramer
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the enzyme consists of a large catalytic and a small regulatory subunit, two copies of which form the enzyme tetramer
STORAGE STABILITY
ORGANISM
UNIPROT
LITERATURE
0-4°C, 50 mM potassium phosphate, pH 7.0, 10 mM mercaptoethanol, 1 mM MgCl2, 0.01 mM thiamine diphosphate, 1 month, 20% loss of activity
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PURIFICATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
APPLICATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
REF.
AUTHORS
TITLE
JOURNAL
VOL.
PAGES
YEAR
ORGANISM (UNIPROT)
PUBMED ID
SOURCE
Arfin, S.M.; Koziell, D.A.
Acetolactate synthase of Pseudomonas aeruginosa I. Purification and allosteric properties
Biochim. Biophys. Acta
321
348-355
1973
Pseudomonas aeruginosa
Arfin, S.M.; Koziell, D.A.
Acetolactate synthase of Pseudomonas aeruginosa. II. Evidence for the presence of two nonidentical subunits
Biochim. Biophys. Acta
321
356-360
1973
Pseudomonas aeruginosa
Gokhale, K.; Tilak, B.
Mechanisms of bacterial acetohydroxyacid synthase (AHAS) and specific inhibitors of Mycobacterium tuberculosis AHAS as potential drug candidates against tuberculosis
Curr. Drug Targets
16
689-699
2015
Saccharomyces cerevisiae, Mycobacterium tuberculosis, Mycobacterium tuberculosis (P9WG41 and P9WKJ3), Pseudomonas aeruginosa, Salmonella enterica subsp. enterica serovar Typhimurium, Escherichia coli (P00892 and P0ADG1), Escherichia coli (P00893 and P00894), Escherichia coli (P08142 and P0ADF8), Mycobacterium tuberculosis H37Rv (P9WG41 and P9WKJ3)
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Release 2023.1 (January 2023)
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