Cyclooxygenases

Cyclooxygenases

Fatty Acid Cyclooxygenases (COX) catalyze the first step in the synthesis of prostaglandins from arachadonic acid, itself derived from dietary linoleic acid.

COX is in fact only one of the catalytic activities of prostaglandin endoperoxide synthase, the other being peroxidase and is found as two isozymes, COX-1 and COX-2.

COX-1 is made constitutivelyt in most tissues and is responsble for maintenance of healthy gastic tissue, renal homeostasis, and platelet aggregation.

COX-2 is inducible in a limited number of tissues in response to products of activated immune and inflammatory cells.

The slightly larger active site of COX-2 allows for COX-2-specific drugs, such as Vioxx.