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Protein / target

Plasma protease C1 inhibitor

Encoded bySERPING1P05155Homo sapiensSwiss-Prot
Clinically validated
Therapeutic maturity
1
Approved medicines
Open Targets target-level
Antibody-tractable
Druggability
UniProt loc high conf
1
Research papers

Protein at a glance

Biological role

Serine-type endopeptidase inhibitor

Strongest disease association

Angioedema

Via encoding gene SERPING1 · Genetic evidence · score 0.86

Therapeutic position

Established drug target

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

Serine protease inhibitor, which acrs as a regulator of the classical complement pathway.

View complete UniProt function annotation

Serine protease inhibitor, which acrs as a regulator of the classical complement pathway (PubMed:10946292, PubMed:11527969, PubMed:3458172, PubMed:6416294). Forms a proteolytically inactive stoichiometric complex with the C1r or C1s proteases (PubMed:10946292, PubMed:3458172, PubMed:6416294). May also regulate blood coagulation, fibrinolysis and the generation of kinins (PubMed:8495195). Very efficient inhibitor of FXIIa. Inhibits chymotrypsin and kallikrein (PubMed:8495195)

Subcellular location

Secreted
Domains and Gene Ontology detail (12)

Gene Ontology

  • Cblood microparticle
  • Cendoplasmic reticulum lumen
  • Cextracellular exosome
  • Cextracellular matrix
  • Cextracellular region
  • Cextracellular space
  • Cplatelet alpha granule lumen
  • Fserine-type endopeptidase inhibitor activity
  • Pblood circulation
  • Pblood coagulation
  • Pfibrinolysis
  • Pnegative regulation of complement activation, lectin pathway

500 aa · 55 kDa · 3 isoforms

Biological roles

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

HaemostasisUniProt · GO
View supporting evidence

Haemostasis

  • ·Serine protease inhibitor, which acrs as a regulator of the classical complement pathway…
  • ·platelet alpha granule lumen
  • ·blood coagulation
  • ·fibrinolysis

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 SERPING1

Gene-level evidence surfaced through the gene SERPING1 that 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.

Angioedemas, Hereditary
0.95Well supported

Genetic evidence dominant · Open Targets 0.73

Angioedema
0.93Well supported

Genetic evidence dominant · Open Targets 0.62

Genetic Diseases, Inborn
0.86Well supported

Genetic evidence dominant · Open Targets 0.53

Asthma
0.78Well supported

Genetic evidence dominant · Open Targets 0.48

View evidence synthesis (4)
Angioedemas, HereditaryWell supported
0.95
agreement 0.841.00
Genetic49%Clinical42%Literature9%Genetic literaturedup

Open Targets aggregate 0.73 · 3 independent evidence families · 1 not counted as duplicate

AngioedemaWell supported
0.93
agreement 0.821.00
Genetic62%Clinical29%Literature9%

Open Targets aggregate 0.62 · 3 independent evidence families

Genetic Diseases, InbornWell supported
0.86
agreement 0.721.00
Genetic97%Literature3%

Open Targets aggregate 0.53 · 2 independent evidence families

AsthmaWell supported
0.78
agreement 0.650.91
Genetic91%Literature6%RNA expression3%

Open Targets aggregate 0.48 · 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
Angioedemas, Hereditary0.73
Angioedema0.62
Genetic Diseases, Inborn0.53
Asthma0.48

Drug development

1 compounds recorded · 1 approved

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

View all recorded compounds (1)
CONESTAT ALFAApproval

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

AntibodiesEmerging

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

Protein degradersEmerging

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

Other modalitiesStrong

Approved Drug support this modality.

View underlying tractability evidence (5)
AB · UniProt loc high confAB · GO CC high confAB · UniProt SigP or TMHMMPR · Half-life DataOC · Approved Drug

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

Longhurst HJ · The New England journal of medicine · 2024

Recent

CRISPR-Cas9 In Vivo Gene Editing of <i>KLKB1</i> for Hereditary Angioedema.

Longhurst HJ · The New England journal of medicine · 2024

Europe PMC papers linked directly to this protein.