Answer to Question #85998 in Biochemistry for Inder Kumar

Question

Explain the role of uncouplers in electron transport chain or oxidative phosphorylation.Illustrate the answer with the help of an example.

Answer 1

Uncouplers are the substances that reduce the magnitude of the electrochemical gradient increasing the speed of movement of electrons through the enzymes of the respiratory chain, decreasing ATP synthesis, and increasing catabolism. Uncouplers separate the processes of oxidation and phosphorylation of the inner mitochondrial membrane. The uncouplers include protonophores that are the substances that carry hydrogen ions. At the same time, both components of the electrochemical gradient (electric and chemical) are reduced, and the energy of the gradient is dissipated as heat. The effect of protonophores is associated with the increase in the catabolism of fats and carbohydrates in the cell and body. Dinitrophenol is a common protonophore. It is a fat-soluble compound that attaches hydrogen ions on the outer surface of the inner mitochondrial membrane and renders them on the inner surface. Protein thermogenin is a physiological protonophore. Other protonophores include salicylates, fatty acids, and triiodothyronine.