4.3.1.B2: imidazole glycerol phosphate synthase
This is an abbreviated version!
For detailed information about imidazole glycerol phosphate synthase, go to the full flat file.
Word Map on EC 4.3.1.B2
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4.3.1.B2
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glutaminase
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ammonia
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amidotransferase
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maritima
-
thermotoga
-
allostery
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cyclase
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prfar
-
ribonucleotide
-
heterodimeric
-
bienzyme
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aicar
-
millisecond
-
5-aminoimidazole-4-carboxamide
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betaalpha8-barrels
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v-type
-
half-barrels
-
timescale
-
ribotide
- 4.3.1.B2
- glutaminase
- ammonia
-
amidotransferase
- maritima
-
thermotoga
-
allostery
- cyclase
-
prfar
- ribonucleotide
-
heterodimeric
-
bienzyme
- aicar
-
millisecond
- 5-aminoimidazole-4-carboxamide
-
betaalpha8-barrels
-
v-type
-
half-barrels
-
timescale
- ribotide
Reaction
Synonyms
HIS7, IGP synthase, IGPS, ImGP synthase
ECTree
4.3.1.B2 imidazole glycerol phosphate synthaseAdvanced search results
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results (Substrates Products
Substrates Products on EC 4.3.1.B2 - imidazole glycerol phosphate synthase
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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
L-glutamine + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-monophosphate
L-glutamate + D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
L-glutamine + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate
L-glutamate + D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
L-glutamine + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate
L-glutamate + D-erythro-imidazole-glycerol-phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
-
-
-
?
N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate + L-glutamine
L-glutamate + D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
for the IGP synthase holoenzyme L-glutamine is a more efficient substrate relative to ammonium ion by a factor of 1000. The HisF subunit alone does not ulilize L-glutamine. It supports an ammonia-dependent reaction with a turnover number similar to that of the holoenzyme with glutamine
D-erythro-1-(imidazol-4-yl)glycerol phosphate i.e. (2R,3S)-2,3-dihydroxy-3-(1H-imidazol-4-yl)propyl phosphate. 5-Amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide i.e. [(2R,3S,4R,5R)-5-(4-carbamoyl-5-aminoimidazol-1-yl)-3,4-dihydroxyoxolan-2-yl]methyl phosphate i.e. AICAR
-
?
N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate + NH3
D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate + NH4+
D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
the protein encoded by the hisF gene has an ammonia-dependent activity, it does not utilize L-glutamine as substrate. The ammonia-dependent reaction is completely independent of the HisH protein
D-erythro-1-(imidazol-4-yl)glycerol phosphate i.e. (2R,3S)-2,3-dihydroxy-3-(1H-imidazol-4-yl)propyl phosphate. 5-Amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide i.e. [(2R,3S,4R,5R)-5-(4-carbamoyl-5-aminoimidazol-1-yl)-3,4-dihydroxyoxolan-2-yl]methyl phosphate i.e. AICAR
-
?
NH4+ + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate
D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
L-glutamine + H2O
L-glutamate + NH3
the enzyme constitutes a bienzyme complex of the glutaminase subunit HisH and the synthase subunit HisF. Nascent ammonia produced by HisH reacts at the active site of HisF with N'-((5'-phosphoribulosyl)formimino)-5-aminoimidazole-4-carboxamide-ribonucleotide to yield the products imidazoleglycerol phosphate and 5-aminoimidazole-4-carboxamide ribotide. Isolated subunit HisH shows no detectable glutaminase activity but is stimulated by complex formation with subunit HisF to which either the product imidazole glycerol phosphate or a substrate analogue are bound
-
-
?
L-glutamine + H2O
L-glutamate + NH3
the enzyme constitutes a bienzyme complex of the glutaminase subunit HisH and the synthase subunit HisF. Nascent ammonia produced by HisH reacts at the active site of HisF with N'-((5'-phosphoribulosyl)formimino)-5-aminoimidazole-4-carboxamide-ribonucleotide to yield the products imidazoleglycerol phosphate and 5-aminoimidazole-4-carboxamide ribotide. Isolated subunit HisH shows no detectable glutaminase activity but is stimulated by complex formation with subunit HisF to which either the product imidazole glycerol phosphate or a substrate analogue are bound
-
-
?
L-glutamine + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-monophosphate
L-glutamate + D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
the enzyme catalyzes two different reactions at two separate active sites. At the glutaminase active site, glutamine is hydrolyzed to glutamate and ammonia, which, at the synthase active site, reacts with the acceptor substrate N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-monophosphate. Ammonia is channeled between glutaminase and synthase active sites
-
-
?
L-glutamine + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-monophosphate
L-glutamate + D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
the enzyme constitutes a bienzyme complex of the glutaminase subunit HisH and the synthase subunit HisF. Nascent ammonia produced by HisH reacts at the active site of HisF with N'-((5'-phosphoribulosyl)formimino)-5-aminoimidazole-4-carboxamide-ribonucleotide to yield the products imidazole glycerol phosphate and 5-aminoimidazole-4-carboxamide ribotide. Isolated subunit HisH shows no detectable glutaminase activity but is stimulated by complex formation with subunit HisF to which either the product imidazole glycerol phosphate or a substrate analogue are bound
-
-
?
L-glutamine + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-monophosphate
L-glutamate + D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
the enzyme catalyzes two different reactions at two separate active sites. At the glutaminase active site, glutamine is hydrolyzed to glutamate and ammonia, which, at the synthase active site, reacts with the acceptor substrate N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-monophosphate. Ammonia is channeled between glutaminase and synthase active sites
-
-
?
L-glutamine + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-monophosphate
L-glutamate + D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
the enzyme constitutes a bienzyme complex of the glutaminase subunit HisH and the synthase subunit HisF. Nascent ammonia produced by HisH reacts at the active site of HisF with N'-((5'-phosphoribulosyl)formimino)-5-aminoimidazole-4-carboxamide-ribonucleotide to yield the products imidazole glycerol phosphate and 5-aminoimidazole-4-carboxamide ribotide. Isolated subunit HisH shows no detectable glutaminase activity but is stimulated by complex formation with subunit HisF to which either the product imidazole glycerol phosphate or a substrate analogue are bound
-
-
?
L-glutamine + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate
L-glutamate + D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
-
-
-
?
L-glutamine + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate
L-glutamate + D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
-
-
-
?
L-glutamine + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate
L-glutamate + D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
-
-
-
-
?
L-glutamine + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate
L-glutamate + D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
-
-
-
?
L-glutamine + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate
L-glutamate + D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
the imidazole glycerol phosphate synthase catalyzes formation of the imidazole ring in histidine biosynthesis
-
-
?
L-glutamine + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate
L-glutamate + D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
the enzyme is also a glutamine amidotransferase, which produces ammonia in a glutaminase active site and channels it through a 30 A internal tunnel to a cyclase active site
-
-
?
L-glutamine + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate
L-glutamate + D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
-
-
-
-
?
L-glutamine + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate
L-glutamate + D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
-
-
-
-
?
L-glutamine + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate
L-glutamate + D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
-
the enzyme catalyzes a step in the histidine biosynthetic pathway located at the branch point to de novo purine biosynthesis
-
-
?
L-glutamine + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate
L-glutamate + D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
Thermus thermophilus HB8 / ATCC 27634 / DSM 579
-
-
-
-
?
L-glutamine + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate
L-glutamate + D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
Thermus thermophilus HB8 / ATCC 27634 / DSM 579
-
the enzyme catalyzes a step in the histidine biosynthetic pathway located at the branch point to de novo purine biosynthesis
-
-
?
N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate + NH3
D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
the protein encoded by the hisF gene has an ammonia-dependent activity, it does not utilize L-glutamine as substrate. The ammonia-dependent reaction is completely independent of the HisH protein
D-erythro-1-(imidazol-4-yl)glycerol phosphate i.e. (2R,3S)-2,3-dihydroxy-3-(1H-imidazol-4-yl)propyl phosphate. 5-Amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide i.e. [(2R,3S,4R,5R)-5-(4-carbamoyl-5-aminoimidazol-1-yl)-3,4-dihydroxyoxolan-2-yl]methyl phosphate i.e. AICAR
-
?
N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate + NH3
D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
the enzyme constitutes a bienzyme complex of the glutaminase subunit HisH and the synthase subunit HisF. Nascent ammonia produced by HisH reacts at the active site of HisF with N'-((5'-phosphoribulosyl)formimino)-5-aminoimidazole-4-carboxamide-ribonucleotide to yield the products imidazole glycerol phosphate and 5-aminoimidazole-4-carboxamide ribotide. Isolated subunit HisH shows no detectable glutaminase activity but is stimulated by complex formation with subunit HisF to which either the product imidazole glycerol phosphate or a substrate analogue are bound
-
-
?
N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate + NH3
D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
the enzyme constitutes a bienzyme complex of the glutaminase subunit HisH and the synthase subunit HisF. Nascent ammonia produced by HisH reacts at the active site of HisF with N'-((5'-phosphoribulosyl)formimino)-5-aminoimidazole-4-carboxamide-ribonucleotide to yield the products imidazole glycerol phosphate and 5-aminoimidazole-4-carboxamide ribotide. Isolated subunit HisH shows no detectable glutaminase activity but is stimulated by complex formation with subunit HisF to which either the product imidazole glycerol phosphate or a substrate analogue are bound
-
-
?
NH4+ + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate
D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
-
-
-
?
NH4+ + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate
D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
-
-
-
?
NH4+ + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate
D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
-
-
-
-
?
NH4+ + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate
D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
-
-
-
?
NH4+ + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate
D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
-
-
-
-
?
NH4+ + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate
D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide
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-
-
-
?
additional information
?
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the glutaminase activity for the holoenzyme is 0.8% of that in the presence of the nucleotide substrate N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate
-
-
?
additional information
?
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-
the glutaminase activity for the holoenzyme is 0.8% of that in the presence of the nucleotide substrate N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate
-
-
?
additional information
?
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the enzyme also shows glutaminase activity. The glutaminase activity of the glutaminase domain is tightly regulated by the acceptor substrate domain. In IGP synthase the glutaminase and N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate binding sites are separated by 30 A. Using kinetic analyses of site-specific mutants and molecular dynamic simulations, it is determined that an interdomain salt bridge in IGP synthase between D359 and K196 (approximately 16 A from the N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate binding site) plays a key role in mediating communication between the two active sites. This interdomain contact modulates the glutaminase loop containing the histidine and glutamic acid of the catalytic triad to control glutamine hydrolysis
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-
?
additional information
?
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the enzyme shows a low basal level glutaminase activity that can be enhanced 1000fold in the presence of a nucleotide substrate or analog
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-
?
additional information
?
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the enzyme shows a low basal level glutaminase activity that can be enhanced 1000fold in the presence of a nucleotide substrate or analog
-
-
?
additional information
?
-
the glutaminase activity of the enzyme is stimulated 4900fold in the presence of the acceptor substrate N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate
-
-
?
additional information
?
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-
the glutaminase activity of the enzyme is stimulated 4900fold in the presence of the acceptor substrate N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate
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?
