Synthesis of this compound is rate-limited by an enzyme that the W317X (“w-three-seventeen-x”) mutation truncates in Tourette’s syndrome. This is the main substrate of a copper-dependent enzyme that also metabolizes putrescine and cadaverine. Patients with intolerance for this compound take diamine oxidase (-5[1])supplements (15[1])to break down this compound (-5[1])and avoid scombroid (-5[1])poisoning. (-5[2])The first blockbuster (15[1])drug, cimetidine, (15[1])selectively inhibits parietal cells’ receptors for this compound (15[2])to treat (*) stomach ulcers. (10[1]-5[3])This compound is made by decarboxylating an imidazole-containing (-5[1])amino (10[1])acid. (-5[1])The OTC (10[2]-5[1])drugs loratadine and cetirizine (10[2])block this compound’s (10[2])activity (10[1])after IgE causes its release from (10[1])mast cells, (10[7])preventing (10[2])a (-5[1])runny (10[1])nose (-5[1])and itching. (10[2])For (10[1])10 points, (10[1])seasonal allergies (10[3])are treated by drugs (10[1])that (10[1])target (10[1])what (10[1])inflammatory compound? (10[3])■END■ (10[5]0[1])