EC Number   |
Protein Variants |
Reference |
|---|
    6.3.4.2 | E161K |
specific activity of the mutant URA7-encoded and URA8-encoded enzymes are 2fold greater when compared with the wild-type enzymes. The mutant enzymes are less sensitive to CTP product inhibition with inhibitor constants for CTP of 8.4fold- and 5.5fold greater, respectively, than those of their wild-type counterparts. Cells expressing the E161K mutant enzymes on a multicopy plasmid exhibit an increase in resistance to the pyrimidine poison and cancer therapeutic drug cyclopentenylcytosine and accumulate elevated levels of CTP when compared with cells expressing the wild-type enzymes. Cells expressing the E161K mutation in the URA7-encoded CTP synthetase exhibit an 1.5fold increase in the utilization of the Kennedy pathway for phosphatidylcholine synthesis when compared with control cells. Cells bearing the mutation also exhibit an 1.5fold increase in the synthesis of phosphatidylcholine, 1.3fold for phosphatidylethanolamine and 2fold for phosphatidate and a 1.7fold decrease in synthesis of phosphatidylserine. Cells bearing the e161K mutation exhibit an 1.6fold increase in the ratio of total neutral lipids to phospholipids, an 1.4fold increase in triacylglycerol, a 1.7fold increase in free fatty acids, an1.8fold increase in ergosterol ester and a 1.3fold decrease in diacylgylcerol when compared with control cells |
648976 |
| 6.3.4.2 | E362Q |
turnover number for NH4Cl-dependent GTP synthesis reaction is 1.6fold higher than wild-type value |
661713 |
| 6.3.4.2 | E579A |
HEK 293 cells: no effect on phosphorylation of CTPS1 by glycogen synthase kinase 3 |
674862 |
| 6.3.4.2 | G110A |
affinity of the mutant enzyme for GTP is reduced 2-4fold, enzyme exhibits wild-type NH3-dependent activity and affinity for glutamine, but impaired glutamine-dependent CTP formation |
648962 |
| 6.3.4.2 | G142A |
site-directed mutagenesis, inactive mutant with both ammonia and glutamine |
690817 |
| 6.3.4.2 | G143A |
site-directed mutagenesis, kcat/Km for ammonia-dependent and glutamine-dependent CTP formation by mutant G143A are reduced by 22fold and 16fold, respectively, compared to the wild-type enzyme. The mutant is able to form active tetramers in the presence of ATP and UTP |
690817 |
| 6.3.4.2 | G146A |
site-directed mutagenesis, kcat/Km for ammonia-dependent and glutamine-dependent CTP formation by mutant G143A are reduced by 1.4fold and 1.8fold, respectively, compared to the wild-type enzyme. The mutant is able to form active tetramers in the presence of ATP and UTP |
690817 |
| 6.3.4.2 | G351A |
mutation increases lability of the enzyme, mutant enzyme is not overproduced because of apparent instability and proteolytic degradation |
648980 |
| 6.3.4.2 | G352C |
mutation increases lability of the enzyme, mutation abolishes the capacity to form the covalent glutaminyl-cysteine379 catalytic intermediate, thus preventing glutamine amide transfer function, mutant enzyme is not overproduced because of apparent instability and proteolytic degradation |
648980 |
| 6.3.4.2 | G352P |
mutation increases lability of the enzyme, mutation abolishes the capacity to form the covalent glutaminyl-cysteine379 catalytic intermediate, thus preventing glutamine amide transfer function, mutant enzyme is not overproduced because of apparent instability and proteolytic degradation |
648980 |
