Prostaglandin Endoperoxide Synthetase, also known as cyclooxygenase (COX), is an enzyme involved in the synthesis of prostaglandins and thromboxanes, which are bioactive lipid compounds that regulate various physiological processes in the body. Prostaglandins and thromboxanes are important mediators of inflammation, pain, fever, and blood clotting.
Prostaglandin Endoperoxide Synthetase exists in two isoforms: COX-1 and COX-2. COX-1 is constitutively expressed in most tissues and is involved in maintaining normal physiological functions, such as protecting the stomach lining and regulating blood clotting. On the other hand, COX-2 is primarily induced during inflammation and is responsible for the production of prostaglandins that mediate pain, fever, and the inflammatory response.
The action of Prostaglandin Endoperoxide Synthetase involves converting arachidonic acid, a fatty acid derived from cell membranes, into prostaglandin H2 (PGH2), which is a common precursor for other prostaglandins and thromboxanes. This conversion occurs in a two-step process: first, the enzyme carries out a peroxidase reaction to convert arachidonic acid into prostaglandin G2 (PGG2), and then it catalyzes the endoperoxidase reaction to form prostaglandin H2.
Prostaglandin Endoperoxide Synthetase is the target of nonsteroidal anti-inflammatory drugs (NSAIDs), which inhibit its activity and subsequently reduce pain, fever, and inflammation. Selective COX-2 inhibitors have also been developed to specifically target the inducible COX-
