Prostaglandin-endoperoxide synthase family (Cyclooxygenase family) (COX)

The cyclooxygenase family comprises enzymes that catalyze the committed step in conversion of arachidonic acid to prostaglandin H₂, a precursor for a variety of biologically active prostanoids including prostaglandins, thromboxanes, and prostacyclin. There are two major isoforms in humans: COX-1, which is constitutively expressed and regulates normal physiological functions, and COX-2, which is inducible in response to inflammatory stimuli, cancer, and injury. These enzymes possess dual enzyme activities: cyclooxygenase and peroxidase. Inhibition of COX enzymes by NSAIDs is foundational in the treatment of pain, fever, and inflammation, and COX-2 is a validated oncology target due to its selective upregulation in many cancers. Safety concerns with inhibitors include gastrointestinal, cardiovascular, and renal risks, demanding selective drug targeting and biomarker monitoring. For specific application, further distinction among isoforms (COX-1 vs COX-2) is often needed, but the family as a whole is a well-characterized and medically validated enzyme target.

Other names

COX familyProstaglandin G/H synthasesPTGS family (PTGS1, PTGS2)Prostaglandin synthase (PHS)Prostaglandin synthetase (PHS)Prostaglandin-endoperoxide synthetase (PES)

Competitive or irreversible inhibition of cyclooxygenase active site; Coxibs selectively block COX-2; Aspirin acetylates COX enzymes, irreversibly blocking arachidonic acid binding