An enzyme involved in prostaglandin synthesis that introduces oxygen molecules into arachidonic acid at carbons 9 and 15, forms a peroxide bridge between carbons 9 and 11, and bonds carbons 8 and 12 to form a five-carbon ring. Abbreviated COX.
The enzyme is formally known as prostaglandin-endoperoxide synthase. There are two main isoenzymes, cyclooxygenase I and cyclooxygenase II.
1970s. From cyclo- + oxygen + -ase.