Phosphoribosylglycinamide formyltransferase
| Phosphoribosylglycinamide formyltransferase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
GAR formyltransferase monomer, Human | |||||||||
| Identifiers | |||||||||
| EC no. | 2.1.2.2 | ||||||||
| CAS no. | 2604945 | ||||||||
| Alt. names | 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 | ||||||||
| 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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Phosphoribosylglycinamide formyltransferase (EC 2.1.2.2), also known as glycinamide ribonucleotide transformylase (GAR Tfase), is an enzyme with systematic name 10-formyltetrahydrofolate:5'-phosphoribosylglycinamide N-formyltransferase. This enzyme catalyses the following chemical reaction
- 10-formyltetrahydrofolate + N1-(5-phospho-D-ribosyl)glycinamide tetrahydrofolate + N2-formyl-N1-(5-phospho-D-ribosyl)glycinamide
This tetrahydrofolate (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 Escherichia 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.