Which of the following is a suicidal enzyme?: (A) Lipoxygenase, (B) Cyclooxygenase, (C) 5 ' nucleotidase, (D) Thromboxane synthase
Answer is B. The suicidal enzyme is one, which undergoes self-destruction in order to terminate its own activity, e.g. cyclooxygenase Switching off of prostaglandin activity is paly achieved by a remarkable propey of cyclooxygenase, that of self-catalyzed destruction, i.e. it's a suicidal enzyme. Suicidal inhibition is the conversion of a substrate by the enzyme into a metabolite, which is a potent inhibitor of the enzyme. e.g., xanthine oxidase conves allopurinol to alloxanthine (oxypurinol), which is a more potent inhibitor of allopurinol.