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UniProt functional annotation for Q26998 | ||
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| UniProt code: Q26998. |
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| Organism: | |
Toxoplasma gondii. |
| Taxonomy: | |
Eukaryota; Sar; Alveolata; Apicomplexa; Conoidasida; Coccidia; Eucoccidiorida; Eimeriorina; Sarcocystidae; Toxoplasma. |
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| Function: | |
Catalyzes the conversion of uracil and 5-phospho-alpha-D- ribose 1-diphosphate (PRPP) to UMP and diphosphate. {ECO:0000269|PubMed:9247925}. |
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| Catalytic activity: | |
Reaction=diphosphate + UMP = 5-phospho-alpha-D-ribose 1-diphosphate + uracil; Xref=Rhea:RHEA:13017, ChEBI:CHEBI:17568, ChEBI:CHEBI:33019, ChEBI:CHEBI:57865, ChEBI:CHEBI:58017; EC=2.4.2.9; Evidence={ECO:0000269|PubMed:11773618, ECO:0000269|PubMed:9247925}; |
| Cofactor: | |
Name=Mg(2+); Xref=ChEBI:CHEBI:18420; Evidence={ECO:0000269|PubMed:11773618}; Note=Binds 1 Mg(2+) ion per subunit. The magnesium is bound as Mg-PRPP. {ECO:0000269|PubMed:11773618}; |
| Activity regulation: | |
Allosterically activated by GTP. Binding of GTP leads to 5-time activation of the enzyme. {ECO:0000269|PubMed:11773618}. |
| Biophysicochemical properties: | |
Kinetic parameters: KM=3.5 uM for uracil {ECO:0000269|PubMed:11773618, ECO:0000269|PubMed:9247925}; KM=216 uM for 5-phospho-alpha-D-ribose 1-diphosphate (in the absence of GTP) {ECO:0000269|PubMed:11773618, ECO:0000269|PubMed:9247925}; KM=37.4 uM for 5-phospho-alpha-D-ribose 1-diphosphate (in the presence of GTP) {ECO:0000269|PubMed:11773618, ECO:0000269|PubMed:9247925}; Vmax=0.45 umol/min/mg enzyme {ECO:0000269|PubMed:11773618, ECO:0000269|PubMed:9247925}; |
| Pathway: | |
Pyrimidine metabolism; UMP biosynthesis via salvage pathway; UMP from uracil: step 1/1. |
| Subunit: | |
Monomer. Forms homodimers in presence of substrates and homotetramers in the presence of GTP. {ECO:0000269|PubMed:11773618, ECO:0000269|PubMed:9247925}. |
| Similarity: | |
Belongs to the UPRTase family. {ECO:0000305}. |
Annotations taken from UniProtKB at the EBI.