Prostacyclin synthase

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prostaglandin-I synthase
Prostacyclin synthase 2IAG Chiang et al.png
Cartoon diagram of human prostacyclin synthase. Heme group visible at center. From PDB: 2IAG
EC number
CAS number 65802-86-0
IntEnz IntEnz view
ExPASy NiceZyme view
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum
Gene Ontology AmiGO / EGO
Prostaglandin I2 (prostacyclin) synthase
PDB 2iag EBI.png
PDB rendering based on 2iag.
Available structures
PDB Ortholog search: PDBe, RCSB
External IDs OMIM601699 MGI1097156 HomoloGene37374 IUPHAR: 1356 ChEMBL: 4428 GeneCards: PTGIS Gene
EC number
Species Human Mouse
Entrez 5740 19223
Ensembl ENSG00000124212 ENSMUSG00000017969
UniProt Q16647 O35074
RefSeq (mRNA) NM_000961 NM_008968
RefSeq (protein) NP_000952 NP_032994
Location (UCSC) Chr 20:
49.5 – 49.57 Mb
Chr 2:
167.19 – 167.24 Mb
PubMed search [1] [2]

Prostaglandin-I synthase (EC also known as prostaglandin I2 (prostacyclin) synthase (PTGIS) or CYP8A1 is an enzyme involved in prostanoid biosynthesis that in humans is encoded by the PTGIS gene.[1] This enzyme belongs to the family of cytochrome P450 isomerases.


This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. However, this protein is considered a member of the cytochrome P450 superfamily on the basis of sequence similarity rather than functional similarity. This endoplasmic reticulum membrane protein catalyzes the conversion of prostaglandin H2 to prostacyclin (prostaglandin I2), a potent vasodilator and inhibitor of platelet aggregation. An imbalance of prostacyclin and its physiological antagonist thromboxane A2 contribute to the development of myocardial infarction, stroke, and atherosclerosis.[2]

Unlike most P450 enzymes, PGIS does not require molecular oxygen (O2). Instead it uses its heme cofactor to catalyze the isomerization of prostaglandin H2 to prostacyclin. Prostaglandin H2 is produced by cyclooxygenase in the first committed step of prostaglandin biosynthesis.


The systematic name of this enzyme class is (5Z,13E)-(15S)-9alpha,11alpha-epidioxy-15-hydroxyprosta-5,13-dienoate 6-isomerase. Other names in common use include prostacyclin synthase, prostacyclin synthetase, prostagladin I2 synthetase, PGI2 synthase, PGIS, PTGIS, and PGI2 synthetase.


Thromboxane synthesis
Eicosanoid synthesis.

See also[edit]


  1. ^ Yokoyama C, Yabuki T, Inoue H, Tone Y, Hara S, Hatae T, Nagata M, Takahashi EI, Tanabe T (September 1996). "Human gene encoding prostacyclin synthase (PTGIS): genomic organization, chromosomal localization, and promoter activity". Genomics 36 (2): 296–304. doi:10.1006/geno.1996.0465. PMID 8812456. 
  2. ^ "Entrez Gene: PTGIS". 

Further reading[edit]

External links[edit]

This article incorporates text from the United States National Library of Medicine, which is in the public domain.