Metabolic Poisons

Metabolic Poisons are enzyme inhibitors that interfere with the biochemical pathways that are involved in energy production or utilization.

Metabolic poisons work to prevent enzymes from performing their necessary functions during metabolic processes such as cellular respiration, causing a disturbance in the organism's ability to function.

Irreversible metabolic poisons permanently eradicate the activity of an enzyme. This is achieved by forming stable, often covalent, bonds with the enzyme which are strong stable interactions that can only be removed chemically.

Many of these poisons are also irreversible which means that the pathway is completely blocked, stopping respiration entirely and having a more drastic and dangerous effect on the organism and its energy production.

The three kinds of metabolic poisons affect cellular respiration in the same way although they have different characteristics and act at different types during cellular respiration.

- Electron Transport Inhibitors

- Uncoupling Agents

- Oligomycin

These work by preventing electrons from being passed from one carrier to the next by binding to a particular carrier in the ETC.

Cyanide is a lethal example which inhibits oxygen consumption of mitochondria. Rotenone is a competitive inhibitor of electron transport that blocks respiration through NADH. It is used as a pesticide due to its harmful effect on insects.

Uncoupling is when the irreversible dissipation of the chemiosmotic gradient occurs. This leads to a condition in which the rate of electron transport can no longer be regulated.

Uncoupling Agents

Example: DNP

DNP works by binding on the side of the membrane with the greatest proton concentration, making it impossible to maintain the essential gradient and leading to uncoupling reactions.

Metabolic Poisons

In the past, this was used as a dietary pill since during respiration it lead to energy being released as heat instead of stored as fat, causing rapid weight loss but also eventually death.

By: Natasha, Sana, Gilbert, and David

Example: FCCP

FFCP acts as an ionophore, completely dissipating the chemiosmotic gradient, leaving the electron transport system uninhibited.

Different Types

Effects on Respiration

Formation of Irreversible Inhibitors

Background Information

ETC Inhibitors

Effect of Oligomycin on Cellular Respiration

Oligomycin

Bibliography:

This is an irreversible antibiotic which binds to ATP synthase in order to block the proton channel, leading to the inhibition of oxidative phosphorylation.

Effect of Irreversible Inhibitors

• http://www.ruf.rice.edu/~bioslabs/studies/mitochondria/mitopoisons.html
• http://www.fastbleep.com/biology-notes/40/116/1158
• http://www.bmb.leeds.ac.uk/illingworth/oxphos/poisons.htm
• http://www.niaid.nih.gov/TOPICS/BIODEFENSERELATED/CHEMICALCOUNTERMEASURES/RESEARCHAREAS/CELLULARRESPIRATION/Pages/chemCellResp.aspx

Visit the wiki page for more information!

http://drhmths1415.pbworks.com/w/page/88413311/Metabolic%20Poisons