Question

List the inhibitors of ETC , Oxidative phosphorylation and their specific targets / (actions) describe briefly

Answer 1

The inhibitors of Electron Transport Chain (ETC) are the substances that bind the components of the ETC and thus block the transfer of electrons through the ETC. This results in the inhibition of synthesis of the ATP in the mitochondria by oxidative phosphorylation.

Some important inhibitors of ETC are as:

1. Amytal : This inhibitor binds the complex I of the ETC. It prevents the transfer of electrons from the complex I ( NADH -Q Oxidoreductase) to ubiquinone.

2. Rotenone: This inhibitor also binds complex  I of the ETC. It also blocks the transfer of electrons from complex I to ubiquinone.

3. Antimycin A: The inhibitor binds the complex III of the ETC and blocks the transfer of electrons from cytochrome b to cytochrome C_{​​​​​​1 .}

4. Cyanide: The inhibitor binds to the complex IV ( Cytochrome Oxidase) of the ETC and blocks electron transfer thus inhibits ATP synthesis.

5. Carbon Monoxide: This inhibitor also blocks the complex IV of the ETC.

6. Sodium Azide: The inhibitor again binds to the heme groups of the cytochrome oxidase of the complex IV of the ETC and blocks electron transfer and hence generation of proton gradient across the inner mitochondrial membrane.

7. Aurovertin: This inhibitor binds the complex V ( ATP Synthase complex) of the ETC. It F1 subunit of the complex.

8. Oligomycin: This inhibitor also binds to ATP Synthase complex inhibits F_{​​​​​​o} and CF_{​​​​​o}.