Adenosine triphosphates cyanide

Since active transport often requires energy in the form of adenosine triphosphate (ATP), compounds or conditions that inhibit energy production (e.g., iodoac-etate, fluoride, cyanide, anaerobiosis) will impair active transport. The transport of a given compound also can be inhibited competitively by the coadministration of other compounds of sufficient structural similarity that they can compete with the first substance for sites on the carrier protein. 

The toxic effect of cyanide is attributed predominantly to the production of anoxia following inhibition of the metal-containing enzymes. The critical interaction appears to be the inhibition of the terminal respiratory chain enzyme, cytochrome oxidase as (containing iron) within the mitochondria. The enzyme is essential for the production of adenosine triphosphate (ATP). As a result, aerobic oxidative... 

Both hydrogen cyanide (HCN) and hydrogen sulfide (H2S) are metabolic poisons that act in relatively similar mechanistic ways. At the cellular level, the major energy source is adenosine triphosphate (ATP). 

Cyanide is described as a cellular toxin because it inhibits aerobic metabolism. It reversibly binds with ferric (Fe " ") iron-containing cytochrome oxidase and inhibits the last step of mitochondrial oxidative phosphorylation. This inhibition halts carbohydrate metabolism from citric acid cycle, and intracellular concentrations of adenosine triphosphate are rapidly depleted. When absorbed in high enough doses, respiratory arrest quickly ensues, which is probably caused by respiratory muscle failure. Cardiac arrest and death inevitably follow. 

The toxicity of cyanide is attributed to its ability to inhibit enzyme reactions. The action of one such enzyme, cytochrome oxidase, essential for the respiration of cells is inhibited by cyanide ions. Cytochrome oxidase is a component of the mitochondrial electron transport system. It transfers electrons from cytochrome c to oxygen, forming water, while releasing sufficient free energy to permit the formation of adenosine 5 -triphosphate (ATP). The latter is essential for normal metabolic processes. Cyanide ion forms complexes with heavy metal ions such as iron and copper to stop electron transport and thus prevent ATP formation. Several enzyme reactions have been listed that cyanide can inhibit several enzyme reactions by forming complexes. 

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