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MS
rate-limiting unreviewed

Glutamine-PRPP amidotransferase

1 reactions · 1 pathways

Cofactors used

Clinical / pharmacological. Committed step of purine synthesis; feedback-inhibited by AMP/GMP; azaserine site

What it does, reaction by reaction

1 reactions

Purine De Novo Synthesis (IMP synthesis through to AMP/GMP) Nucleotide Metabolism · Cytosol

step 2 Irreversible rate-limiting

PRPP → 5-phosphoribosylamine (5-PRA)

Converts PRPP into 5-Phosphoribosylamine

Notes

Glutamine-PRPP amidotransferase catalyzes PRPP + glutamine + H2O → 5-PRA + glutamate + PPi. The enzyme uses an internal glutaminase domain to generate ammonia, which is channeled to the phosphoribosyl-transferase domain; PPi hydrolysis drives the reaction forward. This is the committed, rate-limiting, and effectively irreversible step of de novo purine synthesis.

Showing all 1 reactions.

What accelerates and inhibits it

Regulation is pathway-specific, so each context is listed separately

1 entries

Purine De Novo Synthesis (IMP synthesis through to AMP/GMP)

Accelerated by

PRPP

Inhibited by

IMP, AMP, and GMP (feedback inhibition; combined nucleotide pools are most effective)

Hormonal control

No established direct endocrine regulation; expression/flux increase with growth signals and proliferation.

Recent literature

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