Protein / target

Prostaglandin G/H synthase 1

PTGS1P23219Homo sapiensSwiss-Prot
Clinically validated
Therapeutic maturity
56
Approved medicines
30
Clinical trials
Small-molecule tractable
Druggability
Approved Drug

Protein at a glance

Biological role

Prostaglandin-endoperoxide synthase activity

Primary system

Cardiovascular system

Strongest disease association

hemorrhage

Genetic evidence · score 0.26

Therapeutic maturity

Clinically validated target

56 approved medicines against this target

Druggability

Small molecule

Open Targets tractability · Approved Drug

Clinical development

56 approved · 3 in clinical development

30 linked trials

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

Dual cyclooxygenase and peroxidase that plays an important role in the biosynthesis pathway of prostanoids, a class of C20 oxylipins mainly derived from arachidonate ((5Z,8Z,11Z,14Z)-eicosatetraenoate, AA, C20:4(n-6)), with a particular role in the inflammatory response. The cyclooxygenase activity oxygenates AA to the hydroperoxy endoperoxide prostaglandin G2 (PGG2), and the peroxidase activity reduces PGG2 to the hydroxy endoperoxide prostaglandin H2 (PGH2), the precursor of all 2-series prostaglandins and thromboxanes. This complex transformation is initiated by abstraction of hydrogen at carbon 13 (with S-stereochemistry), followed by insertion of molecular O2 to form the endoperoxide bridge between carbon 9 and 11 that defines prostaglandins. The insertion of a second molecule of O2 (bis-oxygenase activity) yields a hydroperoxy group in PGG2 that is then reduced to PGH2 by two electrons (PubMed:7947975). Involved in the constitutive production of prostanoids in particular in the stomach and platelets. In gastric epithelial cells, it is a key step in the generation of prostaglandins, such as prostaglandin E2 (PGE2), which plays an important role in cytoprotection. In platelets, it is involved in the generation of thromboxane A2 (TXA2), which promotes platelet activation and aggregation, vasoconstriction and proliferation of vascular smooth muscle cells (Probable). Can also use linoleate (LA, (9Z,12Z)-octadecadienoate, C18:2(n-6)) as substrate and produce hydroxyoctadecadienoates (HODEs) in a regio- and stereospecific manner, being (9R)-HODE ((9R)-hydroxy-(10E,12Z)-octadecadienoate) and (13S)-HODE ((13S)-hydroxy-(9Z,11E)-octadecadienoate) its major products (By similarity)

Subcellular location

Microsome membraneEndoplasmic reticulum membrane
Domains and Gene Ontology detail (16)

Domains & features

EGF-like

Gene Ontology

  • Ccytoplasm
  • Cendoplasmic reticulum lumen
  • Cendoplasmic reticulum membrane
  • Cextracellular exosome
  • Cneuron projection
  • Cphotoreceptor outer segment
  • Fheme binding
  • Fmetal ion binding
  • Foxidoreductase activity, acting on single donors with incorporation of molecular oxygen, incorporation of two atoms of oxygen
  • Fperoxidase activity
  • Fprostaglandin-endoperoxide synthase activity
  • Pcyclooxygenase pathway

599 aa · 69 kDa · 6 isoforms

Biological roles

Reactome v97

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

Immune signallingUniProtMetabolic enzyme activityGOHaemostasisUniProt
View supporting evidence

Immune signalling

  • ·Dual cyclooxygenase and peroxidase that plays an important role in the biosynthesis path…

Metabolic enzyme activity

  • ·oxidoreductase activity, acting on single donors with incorporation of molecular oxygen,…

Haemostasis

  • ·Dual cyclooxygenase and peroxidase that plays an important role in the biosynthesis path…
View underlying pathways (2)

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

Interaction neighbourhood

STRING v12.0

Proteins with the strongest functional or physical association. Node size and line weight reflect STRING confidence; hover or select a partner to inspect one association.

PTGISPTGESALOX5PTGES2ALOX15ALOX12PTGES3PTGDSHPGDSPTGS2PTGS1

10 strongest partners — larger node and heavier line mean higher confidence

Functional and physical associations from STRING v12.0. Only associations with this protein are drawn — partner-to-partner links are not part of this evidence.

Drugs targeting this protein

1

Whether each drug engages this protein directly or through a complex, and how many other targets are recorded for it. Direct binders with few recorded targets are listed first.

Aspirin
ApprovedInhibitor

Cyclooxygenase inhibitor

Appears in clinical studies involving Headache, arthritic joint disease, Muscle spasm, Pain

Acts on a complex — shared with PTGS2 · 1 of 2 recorded protein targets — narrow recorded profile

ChEMBL mechanism, action type and target identity. Open Targets clinical status and indications.

Translational evidence

Open Targets 26

Why this target matters therapeutically — disease associations, drugs in development, tractability and safety, from Open Targets.

Strongest genetic associations

Human genetic evidence — the most direct causal link between this target and a disease.

hemorrhage0.26

Genetic · overall 0.63

Highest-confidence therapeutic associations

Diseases where a drug acting on this target has already reached clinical development.

Pain1.00

Clinical · overall 0.61

osteoarthritis1.00

Clinical · overall 0.61

rheumatoid arthritis1.00

Clinical · overall 0.62

Dysmenorrhea1.00

Clinical · overall 0.61

gout1.00

Clinical · overall 0.61

Highest overall evidence

Remaining associations by Open Targets' aggregated evidence score.

ulcerative colitis0.61

Clinical

migraine disorder0.61

Clinical

Headache0.61

Clinical

Fever0.61

Clinical

Show all associations
hemorrhage0.63
rheumatoid arthritis0.62
osteoarthritis0.61
gout0.61
ulcerative colitis0.61
Pain0.61
Dysmenorrhea0.61
migraine disorder0.61
Headache0.61
Fever0.61

Open Targets ranks 1,290 associations for this target and we store the top 10 by aggregated score. The long tail is largely literature co-mention and RNA-expression evidence, not evidence that this target drives those diseases.

Known drugs · 64 total

INDOMETHACINApproval

spondylitis · osteoarthritis · gout

ASPIRINApproval

Headache · arthritic joint disease · Muscle spasm

ESFLURBIPROFENApproval

Pain · osteoarthritis · inflammation

DIFLUNISALApproval

osteoarthritis · rheumatoid arthritis · Pain

TOLMETIN SODIUMApproval

osteoarthritis · rheumatoid arthritis

MECLOFENAMIC ACIDApproval

ankylosing spondylitis · Arthralgia · rheumatic disorder

GLAFENINEApproval

Fever · Pain

DICLOFENAC POTASSIUMApproval

osteoarthritis · Pain · rheumatoid arthritis

DICLOFENACApproval

Dysmenorrhea · osteoarthritis · rheumatoid arthritis

NAPROXEN ETEMESILPhase 2 3

ankylosing spondylitis

Tractability

SM · Approved DrugSM · High-Quality LigandSM · Druggable FamilyAB · UniProt loc med confAB · UniProt SigP or TMHMMPR · Half-life DataPR · Small Molecule BinderOC · Approved Drug

Safety liabilities

Decrease, Population growth rateReduced, Reproductive SuccessDecrease, Population growth rateReduced, Reproductive SuccessReduced, Reproductive SuccessDecrease, Population growth rategastric bleedingN/A, Reproductive failureIncreased MortalityDecrease, Population growth rateDecrease, Population growth rateReduced, Reproductive Success

Clinical trials

30

Trials of drugs that target this protein — reached indirectly through those drugs, so a trial listed here studies the drug, not the protein.

Show remaining trials (24)

COMPLETED · via Aspirin · NCT02906761

ACTIVE_NOT_RECRUITING · via Aspirin · NCT02394769

RECRUITING · via Aspirin · NCT06518317

COMPLETED · via Aspirin · NCT00568152

RECRUITING · via Aspirin · NCT04381936

ClinicalTrials.gov via the drug-target graph.

Related literature

6

Papers indexed under “Cyclooxygenase 1” — a subject heading that covers this protein without being specific to it. Shown as context; not counted as this protein's own research activity.

Metabolism pathways of arachidonic acids: mechanisms and potential therapeutic targets.

Wang B · Signal transduction and targeted therapy · 2021

Prostaglandins and inflammation.

Ricciotti E · Arteriosclerosis, thrombosis, and vascular biology · 2011

Impaired balance of mitochondrial fission and fusion in Alzheimer's disease.

Wang X · The Journal of neuroscience : the official journal of the Society for Neuroscience · 2009

Inflammation and cancer: an ancient link with novel potentials.

Hussain SP · International journal of cancer · 2007

Europe PMC literature, reached through a MeSH descriptor linked to this protein.

Forefront confidence

Synthesis

Our own weighting of the evidence behind each disease association. Human genetics and clinical evidence count for most; literature co-mention counts for little, because two entities sharing an abstract is not evidence that one drives the other.

hemorrhageWell supported
0.80
agreement 0.690.91
Clinical73%Genetic27%Literature0%

Open Targets aggregate 0.63 · 3 independent evidence families

rheumatoid arthritisWell supported
0.76
agreement 0.610.92
Clinical94%Literature6%

Open Targets aggregate 0.62 · 2 independent evidence families

osteoarthritisWell supported
0.76
agreement 0.600.91
Clinical97%Literature3%

Open Targets aggregate 0.61 · 2 independent evidence families

goutWell supported
0.75
agreement 0.600.91
Clinical97%Literature3%

Open Targets aggregate 0.61 · 2 independent evidence families

ulcerative colitisWell supported
0.75
agreement 0.620.89
Clinical96%Literature4%RNA expression0%

Open Targets aggregate 0.61 · 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 underlying per-type scores are shown above so the calculation can be checked.

What's happening now

45

Recent activity around this target, drawn from one canonical event stream. Every item is reached through a drug that targets this protein, so each event is news about that drug rather than about the protein directly.

  1. Supplemental approval2026-06-18

    Supplemental approval: BUTALBITAL, ASPIRIN, CAFFEINE AND CODEINE PHOSPHATE (ANDA074951)

    fda · regulatory · fda · via Aspirin

  2. Supplemental approval2026-06-18

    Supplemental approval: OXYCODONE AND ASPIRIN (ANDA040910)

    fda · regulatory · fda · via Aspirin

  3. Supplemental approval2026-06-18

    Supplemental approval: BUTALBITAL, ASPIRIN, CAFEINE, AND CODEINE PHOSPHATE (ANDA075231)

    fda · regulatory · fda · via Aspirin

  4. Label change2025-12-22

    Label change: BUTALBITAL, ASPIRIN, CAFFEINE AND CODEINE PHOSPHATE (ANDA074951)

    fda · regulatory · fda · via Aspirin

  5. Label change2025-12-22

    Label change: BUTALBITAL, ASPIRIN, CAFEINE, AND CODEINE PHOSPHATE (ANDA075231)

    fda · regulatory · fda · via Aspirin

  6. Label change2025-05-09

    Label change: BUTALBITAL, ASPIRIN, CAFEINE, AND CODEINE PHOSPHATE (ANDA075231)

    fda · regulatory · fda · via Aspirin

  7. Label change2025-03-07

    Label change: OXYCODONE AND ASPIRIN (ANDA040910)

    fda · regulatory · fda · via Aspirin

  8. Label change2024-11-21

    Label change: BUTALBITAL, ASPIRIN, CAFFEINE AND CODEINE PHOSPHATE (ANDA074951)

    fda · regulatory · fda · via Aspirin

  9. Label change2024-11-21

    Label change: OXYCODONE AND ASPIRIN (ANDA040910)

    fda · regulatory · fda · via Aspirin

  10. Supplemental approval2024-10-31

    Supplemental approval: BUTALBITAL, ASPIRIN, CAFFEINE AND CODEINE PHOSPHATE (ANDA074951)

    fda · regulatory · fda · via Aspirin

  11. Supplemental approval2024-10-31

    Supplemental approval: OXYCODONE AND ASPIRIN (ANDA040910)

    fda · regulatory · fda · via Aspirin

  12. Supplemental approval2024-10-31

    Supplemental approval: BUTALBITAL, ASPIRIN, CAFEINE, AND CODEINE PHOSPHATE (ANDA075231)

    fda · regulatory · fda · via Aspirin

Objective event titles are shown unmodified; the event kind and significance line are derived from structured fields. Forefront AttentionEvent stream aggregating Europe PMC Regulatory filings ClinicalTrials.gov.