Cyanide (KCN, hydrogen cyanide, prussic acid, or cyanohydric acid) is a molecule containing carbon and nitrogen joined by a triple bond. The molecule is capable of chelating the iron from heme in the cytochrome complex. Cyanide is rarely found in natural environments at concentrations sufficient to impact respiration. However, researchers have known that cyanide can cause death in mammals since the mid-1700's. Mammals with cyanide poisoning (concentrations above 0.5 mg/kg body weight) are unable to release oxygen from hemoglobin and show symptoms of respiratory distress, paralysis, and coma. Cyanide is a potent irreversible inhibitor of heme in cytochrome c oxidase and concentrations as low as 1 mM can reduce overall Vmax activity to 1% of maximal activity. Since cytochrome c ...
The plants ability to overcome cyanide poisoning is examined. Low levels of cyanide arrests cellular respiration in animals is analyzed.