| Background |
COX proteins are membrane-associated heme proteins that have cyclooxygenase and peroxidase activities. These enzymes are targets of NSAID (Nonsteroidal anti-inflammatory drμgs) such as aspirin. Prostaglandins (PGs) formed by the enzymatic activity of COX-1 are primarily involved in the regulation of homeostatic functions throμghout the body, whereas PGs formed by COX-2 primarily mediate pain, fever, and inflammation. COX-1 is constitutively expressed, with particularly high expression in gastrointestinal tissues. COX-2 is induced by cytokines and mitogens and is likely to play a role in inflammatory diseases such as rheumatoid arthritis. In rodents and humans, COX-3 encodes proteins with completely different amino acid sequences than COX-1 or COX-2 and without COX activity. It has been sμggested COX-3 as the key to unlocking the mystery of the mechanism of action of acetaminophen.
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