This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Structure and function of protein, Subject name: Biochemistry
Which of the following is a suicidal enzyme 
Select and explain. 
A. Cyclooxygenase, B. Lipooxygenase, C. 5-nucleotidase, D. Thrombaxane synthase
A: Cyclooxygenase
Answer: A: Cyclooxygenase 
Explanation: Cyclooxygenase is a "Suicide Enzyme""Switching off " of prostaglandin activity is paly achieved by a remarkable propey of cyclooxygenase--that of self-catalyzed destruction; that is, it is a "suicide enzyme." Fuhermore, the inactivation of prostaglandins by 15-hydroxyprostaglandin dehydrogenase is rapid. Blocking the action of this enzyme with sulfasalazine or indomethacin can prolong the half-life of prostaglandins in the body.Ref: Harper&;s Biochemistry; 30th edition; Chapter 23; Biosynthesis of Fatty Acids & Eicosanoids