Poisons and Drugs that affect Enzyme Activity

• Potassium Cyanide: Non-competitive inhibitor of respiratory enzyme cytochrome oxidase (in mitochondria), aerobic respiration can’t produce ATP (only anaerobic), exposure rapidly causes unconsciousness, followed by death
• Ethylene Glycol: Component of antifreeze in car engines, poisonous if broken down by alcohol dehydrogenase in the liver (makes oxalic acid), itself is non-toxic and so excreted, its a competitive inhibitor for alcohol (treatment: massive dose of alcohol)
• Penicillin: Antibiotic that prevents bacterial cell reproduction by inhibiting an enzyme required for bacterial cell wall synthesis