EC Number   |
Substrates |
Products |
Reversibility |
|---|
    6.3.1.21 | ADP + acetyl phosphate |
only half-reaction |
? |
- |
? |
| 6.3.1.21 | ADP + carbamoyl phosphate |
only half-reaction |
? |
- |
? |
| 6.3.1.21 | ADP + formyl phosphate |
only half-reaction |
? |
- |
? |
| 6.3.1.21 | ATP + acetate + N1-(5-phospho-beta-D-ribosyl)glycinamide |
only half-reaction resulting in formation of ADP and acetylphosphate |
? |
- |
? |
| 6.3.1.21 | ATP + formate + N1-(5-phospho-beta-D-ribosyl)glycinamide |
- |
ADP + phosphate + N2-formyl-N1-(5-phospho-beta-D-ribosyl)glycinamide |
- |
? |
| 6.3.1.21 | ATP + formate + N1-(5-phospho-D-ribosyl)glycinamide |
- |
ADP + H+ + N2-formyl-N1-(5-phospho-D-ribosyl)glycinamide + phosphate |
- |
? |
| 6.3.1.21 | more |
kinetic studies of the wild-type PurT enzyme demonstrate that formyl phosphate behaves as a chemically and kinetically competent intermediate. The requirement for ATP and glycinamide ribonucleotide (GAR) in these reactions is consistent with previous steady-state kinetic results, which have demonstrated that all substrates must be bound before catalysis. Kinetic analysis and positional isotope exchange studies also support the assignment of formyl phosphate as a plausible intermediate. Forward and reverse half-reactions utilizing the proposed intermediate are measured spectrophotometrically. PurT transformylase is capable of generating acetyl phosphate from ATP and acetate. The first half-reaction leads to production of acyl phosphate, the second half-reaction acylates GAR. Neither acetyl GAR nor carbamyl GAR is produced when the enzyme is incubated with ATP, GAR, and the appropriate acid. Neither the reverse first half-reaction with acetyl phosphate nor carbamyl phosphate requires GAR to be present, in contrast to the half-reactions involving formyl phosphate. No activity with aminoformate |
? |
- |
? |
| 6.3.1.21 | more |
radioactive assay monitoring the conversion of [14C]formate to fGAR or [alpha-32P] ATP to ADP. No activity with 10-formyl-5,8-dideazatetrahydrofolate (10-formyl-DDF), 5-formyl-THF, formyl-aminoimidazolecarboxamide ribonucleotide (fAICAR), formylmethionine, and formiminoglutamate as formyl donor. The enzyme shows a side reaction with ATP and acetate: cleavage of ATP in the presence of acetate to generate acetyl phosphate and ADP. The NMR study demonstrates that the purT GAR transformylase reaction proceeds through a transfer of atomic oxygen from formate to the 7-phosphoryl moiety of ATP. One interpretation is the intermediacy of formyl phosphate whose presence is also supported by the identification of acetyl phosphate as a product in the side reaction |
? |
- |
? |
