Uncoupling of cell respiration and oxidative phosphorylation: it’s possible role in obesity

The electron transport chain is the final phase of tissue respiration through which the energy from oxidation of nutrients is converted into an electrochemical gradient. This electrochemical gradient generates a proton motive force which is converted into high energy phosphoanhydride bonds of ATP within the mitochondria. Studies have shown that the transduction of electromotive force into phosphoanhydride bond is not perfect as there is some degree of uncoupling in which the electrochemical gradient is dissipated when protons are returned to the mitochondria not through ATP synthase. This can be in the form of low grade background uncoupling sometimes referred to as proton leakage or it can be due to naturally produced special proteins known as uncoupling proteins with in the inner mitochondrial membrane. Uncoupling tends to decrease ATP synthesis and the energy from oxidation that should have formed ATP is released as heat. Oxidation of nutrients is also increased due to a decrease in ATP synthesis. Here we review the possible role of this uncoupling process in the development of obesity.