6.3.4.2: CTP synthase (glutamine hydrolysing)
This is an abbreviated version!
For detailed information about CTP synthase (glutamine hydrolysing), go to the full flat file.
Word Map on EC 6.3.4.2
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6.3.4.2
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pyrimidine
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cytosine
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cytoophidia
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dctp
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cyclopentenyl
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deoxycytidine
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acivicin
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glutamine-dependent
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3-deazauridine
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rheumatology
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l-glutamine
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alliance
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carra
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ctpas
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pyrazofurin
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uridine-cytidine
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rheumatologist
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6-diazo-5-oxo-l-norleucine
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drug development
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medicine
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analysis
- 6.3.4.2
- pyrimidine
- cytosine
-
cytoophidia
- dctp
-
cyclopentenyl
- deoxycytidine
- acivicin
-
glutamine-dependent
- 3-deazauridine
-
rheumatology
- l-glutamine
-
alliance
-
carra
-
ctpas
- pyrazofurin
-
uridine-cytidine
-
rheumatologist
- 6-diazo-5-oxo-l-norleucine
- drug development
- medicine
- analysis
Reaction
Synonyms
CTP synthase, CTP synthase 1, CTP synthetase, CTP synthetase 1, CTPS, CTPS1, CTPS2, CTPsyn, CTS, cytidine 5'-triphosphate synthase, cytidine 5'-triphosphate synthetase, cytidine triphosphate synthetase, cytidine triphosphate synthetase 1, EcCTPS, pfCTP synthetase, PyrG, synthetase, cytidine triphosphate, URA7, uridine triphosphate aminase, UTP-ammonia ligase, UTP:ammonia ligase (ADP-forming)
ECTree
6.3.4.2 CTP synthase (glutamine hydrolysing)Advanced search results
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results (Specific Activity
Specific Activity on EC 6.3.4.2 - CTP synthase (glutamine hydrolysing)
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SPECIFIC ACTIVITY [µmol/min/mg] 
ORGANISM
UNIPROT
COMMENTARY 
LITERATURE
0.0025
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specific activity of Escherichia coli expressed enzyme, after a 20 min incubation with protein kinase C, the activity of the CTP synthetase was stimulated 95fold
additional information
additional information
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fast assay allows the processing of a large number of samples
additional information
a structure-activity study using a variety of GTP and guanosine analogues reveals that only a few GTP analogues are capable of activating Gln-dependent CTP formation to varying degrees: GTP > 6-thio-GTP > ITP> guanosine 5'-tetraphosphate > O-methyl-GTP > 2'-deoxy-GTP. No activation is observed with guanosine, GMP, GDP, 2',3'-dideoxy-GTP, acycloguanosine, and acycloguanosine monophosphate indicating that the 5'-triphosphate, 2'-OH, and 3'-OH are required for full activation. The 2-NH2 group is important in binding recognition while substituents at the 6-position are important in activation.
additional information
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a structure-activity study using a variety of GTP and guanosine analogues reveals that only a few GTP analogues are capable of activating Gln-dependent CTP formation to varying degrees: GTP > 6-thio-GTP > ITP> guanosine 5'-tetraphosphate > O-methyl-GTP > 2'-deoxy-GTP. No activation is observed with guanosine, GMP, GDP, 2',3'-dideoxy-GTP, acycloguanosine, and acycloguanosine monophosphate indicating that the 5'-triphosphate, 2'-OH, and 3'-OH are required for full activation. The 2-NH2 group is important in binding recognition while substituents at the 6-position are important in activation.
additional information
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CTP synthetase 1 activity of the T455A mutant enzyme is 2fold higher than the wild type enzyme. T455A mutation causes a 44% decrease in the amount of human CTP synthetase 1 that is phosphorylated in Saccharomyces cerevisiae cells, accompanied by a 2.5fold increase in the cellular concentration of CTP and a 1.5-fold increase in the choline-dependent synthesis of phosphatidylcholine
additional information
low serum is found to decrease CTPS1 activity, and incubation with the glycogen synthase kinase 3 inhibitor indirubin-3-monoxime protects against this decrease in activity. Incubation with an alkaline phosphatase increases CTPS1 activity in a time-dependent manner, demonstrating that phosphorylation inhibits CTPS1 activity
additional information
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low serum is found to decrease CTPS1 activity, and incubation with the glycogen synthase kinase 3 inhibitor indirubin-3-monoxime protects against this decrease in activity. Incubation with an alkaline phosphatase increases CTPS1 activity in a time-dependent manner, demonstrating that phosphorylation inhibits CTPS1 activity
additional information
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S462A mutation results in 61%-reduced CTP synthetase 1 phosphorylation. The Saccharomyces cerevisiae-expressed and purified S462A mutant enzyme exhibits a 2fold reduction in CTP synthetase 1 activity, whereas the purified T455A mutant enzyme exhibited a 2fold elevation in CTP synthetase 1 activity, implying that that protein kinase C phosphorylation at Ser462 stimulates human CTP synthetase 1 activity, whereas phosphorylation at Thr455 inhibits activity
additional information
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T455A mutation results in 58%-reduced CTP synthetase 1 phosphorylation. The Saccharomyces cerevisiae-expressed and purified S462A mutant enzyme exhibits a 2fold reduction in CTP synthetase 1 activity, whereas the purified T455A mutant enzyme exhibited a 2fold elevation in CTP synthetase 1 activity, implying that that protein kinase C phosphorylation at Ser462 stimulates human CTP synthetase 1 activity, whereas phosphorylation at Thr455 inhibits activity
additional information
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Thr 455 is identified as a major site of phosphorylation by protein kinase A, phosphorylation at Thr455 results in the inhibition of activity in vitro and in vivo. Data indicate that phosphorylation at Thr455 attenuates the choline-dependent synthesis of phosphatidylcholine when CTP synthetase 1 enzyme is expressed in Saccharomyces cerevisiae
additional information
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during the purification, the specific activity of the enzyme preparation increased 836fold and the total yield is 28%
