Prostacyclin synthase

prostaglandin-I synthase
Cartoon diagram of human prostacyclin synthase. Heme group visible at center. From PDB: 2IAG​
Identifiers
EC no.	5.3.99.4
CAS no.	65802-86-0
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
Gene Ontology	AmiGO / QuickGO
Search PMC articles PubMed articles NCBI proteins

Prostaglandin-I synthase (EC 5.3.99.4) 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. This enzyme belongs to the family of cytochrome P450 isomerases.

Function

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.

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.

Nomenclature

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.

Pathways

Thromboxane synthesis

Eicosanoid synthesis.

Molecular interactions

Generally, protein–protein interactions play crucial roles and are critical for formation of protein microenvironment, cell signaling and direct regulation of the activity of metabolic enzymes. Information on tissue-specific spectrum of molecular interactions of prostacyclin synthase will be useful for subnetwork analysis of PTGIS. Following proteins became known as potential direct binders of PTGIS: CYP2J2, GST, GSTA1, GLRX3, AKR1A1. Protein–protein and protein-peptide interactions were experimentally verified using surface plasmon resonance technology.

See also

• Prostanoid

External links

• prostacyclin+synthetase at the U.S. National Library of Medicine Medical Subject Headings (MeSH)

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