COXentsyymit

COXentsyymit are a family of enzymes that catalyze the first step in the biosynthesis of prostanoids, a group of signaling molecules including prostaglandins and thromboxanes. They convert arachidonic acid to prostaglandin G2 and subsequently to prostaglandin H2, which are precursors for various prostanoids involved in inflammation, pain, vascular tone, and hemostasis. The enzymes are predominantly membrane-bound, located on the endoplasmic reticulum and, in many cells, the nuclear envelope, and function as homodimers comprising cyclooxygenase and peroxidase activities that use a heme prosthetic group.

Within the COXentsyymit family, the best characterized isoforms are COX-1 and COX-2. COX-1 is generally constitutive, supporting routine physiological processes such as gastric mucosal protection and platelet function. COX-2 is inducible and upregulated by inflammatory cytokines, growth factors, and certain tumors. A less certain member, sometimes called COX-3 in early reports, is debated in humans.

Expression and activity of COXentsyymit are controlled at transcriptional and post-translational levels and can be modulated by cellular signaling pathways including NF-kB and MAP kinases. They are targets of nonsteroidal anti-inflammatory drugs (NSAIDs). Aspirin and other NSAIDs inhibit COX activity, with aspirin irreversibly acetylating the enzymes. Selective COX-2 inhibitors aim to reduce inflammation with fewer gastric side effects, though they carry cardiovascular risks.

Biological significance and clinical relevance: COXentsyymit play a central role in inflammatory responses, analgesia, and fever. They also contribute to platelet aggregation and renal function. Abnormal COX regulation is implicated in cancers, cardiovascular disease, and chronic inflammatory conditions. Ongoing research investigates isoform-specific roles and new inhibitors for safer therapies.