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Protein / target

Purine nucleoside phosphorylase

Encoded byPNPP00491Homo sapiensSwiss-Prot
UniProt: P00491Ensembl: ENSG00000198805HGNC: HGNC:7892NCBI Gene: 4860
Clinically validated
Therapeutic maturity
1
Approved medicines
Open Targets target-level
Small-molecule tractable
Druggability
Advanced Clinical
1
Research papers

Protein at a glance

Biological role

Purine-nucleoside phosphorylase

Strongest disease association

Severe Combined Immunodeficiency

Via encoding gene PNP · Genetic evidence · score 0.85

Therapeutic position

Established drug target

Small molecules

Research activity

Emerging research

1 papers · latest 2024

Derived from structured UniProt, Open Targets and literature data on this page.

Protein profile

UniProt 2026_02

Canonical identity and biological annotation from UniProt.

Function overview

Catalyzes the phosphorolytic breakdown of the N-glycosidic bond in the beta-(deoxy)ribonucleoside molecules, with the formation of the corresponding free purine bases and pentose-1-phosphate.

View complete UniProt function annotation

Catalyzes the phosphorolytic breakdown of the N-glycosidic bond in the beta-(deoxy)ribonucleoside molecules, with the formation of the corresponding free purine bases and pentose-1-phosphate (PubMed:23438750, PubMed:3029074, PubMed:9305964). Preferentially acts on 6-oxopurine nucleosides including inosine and guanosine (PubMed:9305964)

Subcellular location

Cytoplasm, cytosol
Domains and Gene Ontology detail (29)

Gene Ontology

  • Ccytoplasm
  • Ccytosol
  • Cextracellular exosome
  • Cextracellular region
  • Cficolin-1-rich granule lumen
  • Csecretory granule lumen
  • Fguanosine phosphorylase activity
  • Fidentical protein binding
  • Fnucleoside binding
  • Fphosphate ion binding
  • Fpurine nucleobase binding
  • Fpurine-nucleoside phosphorylase activity

289 aa · 32 kDa

Biological roles

What this protein does, drawn together from its UniProt function, Gene Ontology terms and Reactome pathways.

Immune signallingGOMetabolic enzyme activityGO
View supporting evidence

Immune signalling

  • ·immune response
  • ·positive regulation of alpha-beta T cell differentiation
  • ·positive regulation of interleukin-2 production
  • ·positive regulation of T cell proliferation

Metabolic enzyme activity

  • ·allantoin metabolic process
  • ·nucleobase-containing compound metabolic process

Concepts derived from UniProt GO Reactome — each badge above shows which sources supported that role.

Translational evidence

Open Targets 26

Why this target matters therapeutically, strongest evidence first. Disease associations are gene-level (via the gene that encodes this protein) and open into the full confidence synthesis; the development universe, tractability and safety annotations are target-level, from Open Targets.

Strongest disease associations · via encoding gene PNP

Gene-level evidence surfaced through the gene PNPthat encodes this protein — not a direct protein–disease relationship. Ranked by Forefront's causal-directness weighting, so genetically- and clinically-evidenced diseases lead over ones that merely share the literature.

Severe Combined Immunodeficiency
0.85Well supported

Genetic evidence dominant · Open Targets 0.63

T-B- severe combined immunodeficiency
0.61Moderately supported

Genetic literature evidence dominant · Open Targets 0.46

mature T-cell and NK-cell non-Hodgkin's lymphoma
0.47Limited support

Clinical evidence dominant · Open Targets 0.38

Genetic Diseases, Inborn
0.32Limited support

Genetic evidence dominant · Open Targets 0.19

Leukemia, Lymphocytic, Chronic, B-Cell
0.16Preliminary

Clinical evidence dominant · Open Targets 0.11

View evidence synthesis (5)
Severe Combined ImmunodeficiencyWell supported
0.85
agreement 0.71–0.99
Genetic97%Literature3%Genetic literaturedup

Open Targets aggregate 0.63 · 2 independent evidence families · 1 not counted as duplicate

T-B- severe combined immunodeficiencyModerately supported
0.61
agreement 0.45–0.76
Genetic literature100%

Open Targets aggregate 0.46 · 1 independent evidence family

mature T-cell and NK-cell non-Hodgkin's lymphomaLimited support
0.47
agreement 0.32–0.63
Clinical100%Literature1%

Open Targets aggregate 0.38 · 2 independent evidence families

Genetic Diseases, InbornLimited support
0.32
agreement 0.18–0.45
Genetic98%Literature2%

Open Targets aggregate 0.19 · 2 independent evidence families

Leukemia, Lymphocytic, Chronic, B-CellPreliminary
0.16
agreement 0.03–0.30
Clinical71%Literature26%RNA expression3%

Open Targets aggregate 0.11 · 3 independent evidence families

The evidence agreement range shows how closely the independent evidence families agree — it is not a statistical confidence interval, and nothing here is fitted to outcome data. Derived from Open Targets evidence types under Forefront weighting; the per-type scores above show the calculation.

Show all associations
Severe Combined Immunodeficiency0.63
T-B- severe combined immunodeficiency0.46
mature T-cell and NK-cell non-Hodgkin's lymphoma0.38
Genetic Diseases, Inborn0.19
Gout0.11
Lymphoma, T-Cell, Cutaneous0.11
Leukemia, Lymphocytic, Chronic, B-Cell0.11

Drug development

3 compounds recorded · 1 approved · 2 in clinical development

Open Targets' development universe — every compound recorded against the target at any stage, not all approved medicines.

View all recorded compounds (3)
FORODESINEPhase 2
ULODESINEPhase 2
FORODESINE HYDROCHLORIDEApproval

Open Targets known-drugs universe. Drug name and highest clinical stage only — the disease relationship is NOT read from this slice (it carries trial-context noise); approved indications come from the canonical graph above.

Tractability

Small molecules — Strong

Advanced Clinical and Structure with Ligand support this modality.

Antibodies — Emerging

Feasibility evidence (go cc high conf) — no clinical-stage drug of this modality recorded.

Protein degraders — Emerging

Feasibility evidence (database ubiquitination and half-life data) — no clinical-stage drug of this modality recorded.

View underlying tractability evidence (9)
SM · Advanced ClinicalSM · Structure with LigandSM · High-Quality LigandSM · High-Quality PocketSM · Druggable FamilyAB · GO CC high confPR · Database UbiquitinationPR · Half-life DataPR · Small Molecule Binder

Raw Open Targets tractability assessment buckets, by modality.

Research activity

1 papers · to 2024

Papers linked directly to this protein. This is the protein's own literature — descriptor-derived papers are kept separate below.

Most cited

MTA-cooperative PRMT5 inhibitors enhance T cell-mediated antitumor activity in MTAP-loss tumors.16 cites

Chen S · Journal for immunotherapy of cancer · 2024

Recent

MTA-cooperative PRMT5 inhibitors enhance T cell-mediated antitumor activity in MTAP-loss tumors.

Chen S · Journal for immunotherapy of cancer · 2024

Europe PMC papers linked directly to this protein.