<prompt> Which of the following is a suicidal enzyme?LipoxygenaseCyclooxygenase5 nucleotidaseThromboxane synthase  <response>: 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. its 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. 