| Abstract: | Non‐shivering thermogenesis is based on the increase of the permeability of the inner membrane of mitochondria to H+. An increase in the H+‐flux from the cytosolic to the matrix compartiment dissipates the electrochemical proton gradient and, therefore, activates the mitochondrial respiratory chain. Permeability of H+ is stimulated by artificial protonophores such as 2,4‐dinitrophenol or the interaction of non‐esterified fatty acids with certain proteins of the inner membrane of mitochondria, called uncoupling proteins (UCPs). UCPs are expressed in various tissues of mammalians, but also in riping plants. Despite of their role in thermogenesis, activated UCPs suppress the formation of the superoxid anion radical. Therefore, UCPs are also physiological tools to diminish oxidative stress within the cell. |
