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unreviewed

Purine nucleoside phosphorylase (PNP)

4 reactions · 2 pathways

Cofactors used

Pi

Clinical / pharmacological. PNP deficiency: T-cell immunodeficiency

What it does, reaction by reaction

4 reactions

Purine Degradation (to Uric Acid) Nucleotide Metabolism · Cytosol

step 5 Irreversible/directional

Inosine → hypoxanthine

Converts Inosine into Hypoxanthine

› Notes

PNP catalyzes inosine + Pi ⇌ hypoxanthine + ribose 1-phosphate. In catabolic tissues, the reaction commonly proceeds toward free hypoxanthine.

step 9 Irreversible/directional

Guanosine → guanine

Converts Guanosine into Guanine

› Notes

PNP catalyzes guanosine + Pi ⇌ guanine + ribose 1-phosphate.

Purine Salvage Pathway Nucleotide Metabolism · Cytosol

step 5 Reversible

Inosine → hypoxanthine + ribose 1-phosphate

Converts Inosine into Hypoxanthine Ribose-1-phosphate

› Notes

Purine nucleoside phosphorylase (PNP) catalyzes inosine + Pi ⇌ hypoxanthine + ribose 1-phosphate. Although this reaction is reversible and is often viewed as degradative, the liberated hypoxanthine can immediately enter the HGPRT reaction in an operational salvage sequence.

step 6 Irreversible/directional

Guanosine → guanine + ribose 1-phosphate

Converts Guanosine into Guanine Ribose-1-phosphate

› Notes

PNP catalyzes guanosine + Pi ⇌ guanine + ribose 1-phosphate. Guanine can then be salvaged by HGPRT; direction in vivo depends on substrate and phosphate concentrations.

Showing all 4 reactions.

What accelerates and inhibits it

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

0 entries

No regulation recorded for this enzyme in the source documents.

Recent literature

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Europe PMC · fetched just now · sorted by publication date

  1. 1
    Unlocking raw-corncob consolidated bioprocessing for malic acid production by DyP-enabled lignin deconstruction in <i>Myceliophthora thermophila</i>.

    Zhang Y, Zhang Y, Han L, Liu J, Liu D, Sun T, Wang D, Li M, Li J, Tian C. · 2026-08-08

    open access unreviewed
  2. 2
    A haplotype-based approach to explore genotype-by-environment interactions for barley yield.

    Brunner SM, Aldiss Z, Alahmad S, Pandit M, Baraibar S, Ganesalingam D, Moody D, Hickey L, Voss-Fels KP, Robin… · 2026-12-01

    open access unreviewed
  3. 3
    A multimodal AI biomarker PATH-ORACLE improves prediction of recurrence in stage I lung adenocarcinoma.

    Kilim O, Pipek O, Sztupinszki Z, Diossy M, Prosz A, Naceur-Lombardelli C, Veeriah S, Moore D, Jamal-Hanjani M… · 2026-09-17

    open access unreviewed
  4. 4
    Nano spray-dried powders for efficient pulmonary delivery of proteins: an emphasis on comparisons of derived metrics determined by chapters <601> and <1604>.

    Li HY, Guo J. · 2026-09-15

    open access unreviewed
  5. 5
    Integrated transcriptomics and metabolomics reveal suppression of the PPAR α/γ pathway linking purine metabolism disorder to high-protein diet-induced hyperuricemia in goslings.

    Li X, Xie Y, Zhang M, Zou T, Zhong C, Rajput ZI, Bi S, Cao L. · 2026-08-04

    open access unreviewed
  6. 6
    Accurate 3D maize ear phenotyping using voxel grids derived from RGB machine vision.

    Oehme LH, Schrag T, Qi P, Stürmer-Stephan B, Ahammad KT, Wanke D, Würschum T, He X, Müller J. · 2026-08-26

    open access unreviewed
  7. 7
    Foliar GR24 and γ-aminobutyric acid modulate redox signaling, root-system architecture, and mineral homeostasis in tellurite-stressed wheat (<i>Triticum aestivum</i> L.).

    Haider I, Rehman SU, Iqbal Z, Mahmood A, Zaheer A, Nadeem MY, Mubushar M, Tahir MU. · 2026-09-11

    open access unreviewed
  8. 8
    Evaluation of subacute toxicity of highly bioavailable curcuRouge® formulation by a repeated dose 28-day oral exposure toxicology study in sprague dawley rats with safety assessment.

    Kapoor MP, Musumi K, Katsuura Y, Aoyama H, Kochizawa M, Tanigaki K, Kishimoto A, Hashimoto T. · 2026-08-27

    open access unreviewed
  9. 9
    Biomaterial-based Drug delivery strategies for head and neck cancer: Local delivery, combination therapy, and translational challenges.

    Li C, Liu Y, Wen Z, Wen J, Cui X, Zhang X. · 2026-08-26

    open access unreviewed
  10. 10
    <i>Bacillus cereus</i> enterotoxins change epithelial barrier function and ion transport in a Caco-2/HT29-MTX co-culture model, provoking inflammation, apoptosis and membrane damage.

    Albahri M, Seeger B, Beineke A, Esatbeyoglu T, Plötz M, Jessberger N. · 2026-09-03

    cited 2× open access unreviewed

External claims. These come from an index outside this database and are not checked against it. Treat them as leads.