EC 6.3.1.21     
Accepted name: phosphoribosylglycinamide formyltransferase 2
Reaction: ATP + formate + N1-(5-phospho-β-D-ribosyl)glycinamide = ADP + phosphate + N2-formyl-N1-(5-phospho-β-D-ribosyl)glycinamide
Other name(s): purT (gene name); GAR transformylase 2; GART2; glycinamide ribonucleotide transformylase 2; 5′-phosphoribosylglycinamide transformylase 2; GAR transformylase T
Systematic name: formate:N1-(5-phospho-β-D-ribosyl)glycinamide ligase (ADP-forming)
Comments: Two enzymes are known to catalyse the third step in de novo purine biosynthesis. This enzyme requires ATP and utilizes formate, which is provided by the hydrolysis of 10-formyltetrahydrofolate by EC 3.5.1.10, formyltetrahydrofolate deformylase. The other enzyme, EC 2.1.2.2, phosphoribosylglycinamide formyltransferase 1, utilizes 10-formyltetrahydrofolate directly. Formyl phosphate is formed during catalysis as an intermediate. The enzyme from the bacterium Escherichia coli can also catalyse the activity of EC 2.7.2.1, acetate kinase.
References:
1.  Nagy, P.L., McCorkle, G.M. and Zalkin, H. purU, a source of formate for purT-dependent phosphoribosyl-N-formylglycinamide synthesis. J. Bacteriol. 175 (1993) 7066–7073. [PMID: 8226647]
2.  Nygaard, P. and Smith, J.M. Evidence for a novel glycinamide ribonucleotide transformylase in Escherichia coli. J. Bacteriol. 175 (1993) 3591–3597. [PMID: 8501063]
3.  Marolewski, A., Smith, J.M. and Benkovic, S.J. Cloning and characterization of a new purine biosynthetic enzyme: a non-folate glycinamide ribonucleotide transformylase from E. coli. Biochemistry 33 (1994) 2531–2537. [PMID: 8117714]
4.  Marolewski, A.E., Mattia, K.M., Warren, M.S. and Benkovic, S.J. Formyl phosphate: a proposed intermediate in the reaction catalyzed by Escherichia coli PurT GAR transformylase. Biochemistry 36 (1997) 6709–6716. [PMID: 9184151]
5.  Thoden, J.B., Firestine, S., Nixon, A., Benkovic, S.J. and Holden, H.M. Molecular structure of Escherichia coli PurT-encoded glycinamide ribonucleotide transformylase. Biochemistry 39 (2000) 8791–8802. [PMID: 10913290]
6.  Jelsbak, L., Mortensen, M.IB., Kilstrup, M. and Olsen, J.E. The in vitro redundant enzymes PurN and PurT are both essential for systemic infection of mice in Salmonella enterica serovar Typhimurium. Infect. Immun. 84 (2016) 2076–2085. [PMID: 27113361]
[EC 6.3.1.21 created 2021]