1 / 8

Effect of Cyanide on ATP S ynthesis

Effect of Cyanide on ATP S ynthesis. Pui Tong HNSC 7210X Nutritional Biochemistry. What is Cyanide?. Cyanide is a chemical compound cyano group C Ξ N Most cyanides are highly toxic Cyanides are produced by certain bacteria, fungi and algae and are found in a number of plants

hector
Download Presentation

Effect of Cyanide on ATP S ynthesis

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Effect of Cyanide on ATP Synthesis Pui Tong HNSC 7210X Nutritional Biochemistry

  2. What is Cyanide? • Cyanide is a chemical compound cyano group CΞN • Most cyanides are highly toxic • Cyanides are produced by certain bacteria, fungi and algae and are found in a number of plants • Commonly used as poison for war or homicides • Many are rapidly absorbed via skin and respiratory and gastrointestinal tract.

  3. Oxidative phosphorylation via Electron Transport Chain

  4. Mechanism of Cyanide • Cyanide anion is an inhibitor of the enzyme cytochrome c oxidase • Cytochrome oxidase complex needed for reduction of oxygen to water • Therefore pathway of oxidative phosphorylation is inhibited and it halts the production of ATP

  5. Signs and symptoms • Intracellular hypoxia • Hypoventilation • Central nervous system manifestations • headache • Confusion • Anxiety • Paralysis • Seizures • Coma • Death

  6. Methods • Rat mesencephalic cell line (N27) was used • After treating the cells with • NaNO2 and/or the • NO scavenger 2-phenyl- 4,4,5,5 tetramethylimidazoline 1 oxy 3 oxide (PTIO) • intracellular NO was measured • Cellular oxygen consumption was monitored • Cellular cytochrome c oxidase (CcOX) activity was measured

  7. Results • Generation of NO from NaNO2 was rapid. • KCN rapidly inhibited oxygen consumption and reduced respiration • Pretreatment with NaNO2 inhibited the effect of KCN • Treatment of carboxy PTIO significantly reversed cyanide inhibition of oxygen consumption by NaNO2 • 10 min after addition of cyanide = ~48% inhibition of CcOX • Preincubation with NaNO2 reduced cyanide inhibition • Pretreatment with PTIO reversed the action of NaNO2

  8. Conclusion • Binding of cyanide to the CcOX can be reversed by antidotes that have high binding affinity for cyanide. • Mechanism of NaNO2 not entirely due to binding of cyanide via mHbbut in part by generation of NO as well. • NaNO2 acts a cyanide antidote by forming NO which displaces cyanide from the CcOX binding site. • The interaction of NO and cyanide at the CcOXheme center alters the kinetics of CcOX to favor O2 binding thus reactivating oxidative phosphorylation. • References: Hamel, Jillian. "A Review of Acute Cyanide Poisoning with a Treatment Update." Critial Care Nurse 31.1 (2011): 71-82. Web. 3 Dec. 2012. • Leavesley, Heather B., Li Li, Soma Mukhopadhyay, Joseph L. Borowitz, and Gary E. Isom. "Nitrite- Mediated Antagonism of Cyanide Inhibition of Cytochrome C Oxidase in Dopamine Neurons." Toxiocological Sciences 115.2 (2010): 569-76. Web. 3 Dec. 2012.

More Related