Cyclooxygenasetype

Cyclooxygenasetype refers to a class of enzymes that play a crucial role in the synthesis of prostaglandins and thromboxanes, collectively known as prostanoids. These enzymes, also called prostaglandin endoperoxide synthases or PTGS, are bifunctional, possessing both cyclooxygenase and peroxidase activities. The cyclooxygenase activity is responsible for the initial conversion of arachidonic acid, a fatty acid, into an unstable intermediate called prostaglandin G2 (PGG2). This involves the oxygenation and cyclization of arachidonic acid. Following this, the peroxidase activity catalyzes the reduction of PGG2 to prostaglandin H2 (PGH2). PGH2 is a pivotal precursor molecule that is then further metabolized by various downstream synthases into a diverse array of biologically active prostanoids, each with specific physiological functions.

There are two main isoforms of cyclooxygenase: 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 gastric mucosa, regulating platelet aggregation, and maintaining kidney function. COX-2, on the other hand, is primarily an inducible enzyme, meaning its expression is upregulated in response to inflammatory stimuli, growth factors, and cytokines. It is therefore predominantly involved in mediating inflammatory processes, pain, and fever. Many nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin and ibuprofen, exert their therapeutic effects by inhibiting cyclooxygenase activity, thereby reducing the production of prostanoids.