PTGS1
Description
The PTGS1 (prostaglandin-endoperoxide synthase 1) is a protein-coding gene located on chromosome 9.
Cyclooxygenase 1 (COX-1), also known as prostaglandin-endoperoxide synthase 1 (HUGO PTGS1), is an enzyme that in humans is encoded by the PTGS1 gene. In humans it is one of two cyclooxygenases. Cyclooxygenase (COX) is the central enzyme in the biosynthetic pathway to prostaglandins from arachidonic acid. This protein was isolated more than 40 years ago and cloned in 1988. There are two isozymes of COX encoded by distinct gene products: a constitutive COX-1 (this enzyme) and an inducible COX-2, which differ in their regulation of expression and tissue distribution. The expression of these two transcripts is differentially regulated by relevant cytokines and growth factors. This gene encodes COX-1, which regulates angiogenesis in endothelial cells. COX-1 is also involved in cell signaling and maintaining tissue homeostasis. A splice variant of COX-1 termed COX-3 was identified in the central nervous system of dogs, but does not result in a functional protein in humans. Two smaller COX-1-derived proteins (the partial COX-1 proteins PCOX-1A and PCOX-1B) have also been discovered, but their precise roles are yet to be described.
PTGS1 encodes a dual cyclooxygenase and peroxidase enzyme that plays a crucial role in the biosynthesis of prostanoids, a class of lipids derived from arachidonic acid. This enzyme catalyzes the conversion of arachidonic acid to prostaglandin G2 (PGG2) through oxygenation, followed by the reduction of PGG2 to prostaglandin H2 (PGH2) via peroxidase activity. PGH2 acts as a precursor for various prostaglandins and thromboxanes. This process involves abstracting hydrogen from carbon 13, incorporating molecular oxygen to form the endoperoxide bridge, and inserting another oxygen molecule to generate the hydroperoxy group. PTGS1 is constitutively expressed in the stomach and platelets, where it contributes to the production of prostanoids. In the stomach, it generates prostaglandins like prostaglandin E2 (PGE2), which protects gastric epithelial cells. In platelets, PTGS1 is involved in the production of thromboxane A2 (TXA2), promoting platelet activation, aggregation, vasoconstriction, and vascular smooth muscle cell proliferation. PTGS1 can also utilize linoleate as a substrate to produce hydroxyoctadecadienoates (HODEs), with (9R)-HODE and (13S)-HODE being the main products.
PTGS1 is also known as COX1, COX3, PCOX1, PES-1, PGG/HS, PGHS-1, PGHS1, PHS1, PTGHS.
