GAR transformylase
| Phosphoribosylglycinamide formyltransferase | |||||||||
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| Identifiers | |||||||||
| EC number | 2.1.2.2 | ||||||||
| CAS number | 2604945 | ||||||||
| Databases | |||||||||
| IntEnz | IntEnz view | ||||||||
| BRENDA | BRENDA entry | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
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| Search | |
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| PMC | articles |
| PubMed | articles |
| NCBI | proteins |
Phosphoribosylglycinamide formyltransferase (EC 2.1.2.2, 2-amino-N-ribosylacetamide 5'-phosphate transformylase, GAR formyltransferase, GAR transformylase, glycinamide ribonucleotide transformylase, GAR TFase, 5,10-methenyltetrahydrofolate:2-amino-N-ribosylacetamide ribonucleotide transformylase) is an enzyme with systematic name 10-formyltetrahydrofolate:5'-phosphoribosylglycinamide N-formyltransferase. This enzyme catalyses the following chemical reaction
This THF dependent enzyme catalyzes a nucleophilic acyl substitution of the formyl group from 10-formyltetrahydrofolate (fTHF) to N1-(5-phospho-D-ribosyl)glycinamide (GAR) to form N2-formyl-N1-(5-phospho-D-ribosyl)glycinamide (fGAR) as shown above. This reaction plays an important role in the formation of purine through the de novo purine biosynthesis pathway. This pathway creates inosine monophosphate (IMP), a precursor to adenosine monophosphate (AMP) and guanosine monophosphate (GMP). AMP is a building block for important energy carriers such as ATP, NAD+ and FAD, and signaling molecules such as cAMP. GARTfase's role in de novo purine biosynthesis makes it a target for anti-cancer drugs and its overexpression during postnatal development has been connected to Down syndrome. There are two known types of genes encoding GAR transformylase in E.coli: purN and purT, while only purN is found in humans. Many residues in the active site are conserved across bacterial, yeast, avian and human enzymes.
In humans, GARTfase is part of trifunctional enzyme which also includes glycinamide ribnucleotide synthase (GARS) and aminoimidazole ribonucleotide synthetase (AIRS). This protein (110kDa) catalyzes steps 2, 3 and 5 of de novo purine biosynthesis. The proximity of these enzyme units and flexibility of the protein serves to increase pathway throughput. GARTfase is located on the C-terminal end of the protein.
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Wikipedia