Canton 1995 Biochem J
|Canton M, Luvisetto S, Schmehl I, Azzone GF (1995) The nature of mitochondrial respiration and discrimination between membrane and pump properties. Biochem J 310:477-81.|
Abstract: A new criterion is utilized for the interpretation of flow-force relationships in rat liver mitochondria. The criterion is based on the view that the nature of the relationship between the H+/O ratio and the membrane potential can be inferred from the relationship between ohmic-uncoupler-induced extra respiration and the membrane potential. Thus a linear relationship between extra respiration and membrane potential indicates unequivocally the independence of the H+/O ratio from the membrane potential and the leak nature of the resting respiration [Brand, Chien, and Diolez (1994) Biochem. J. 297, 27-29]. On the other hand, a non-linear relationship indicates that the H+/O ratio is dependent on the membrane potential. The experimental assessment of this relationship in the presence of an additional ohmic leak, however, is rendered difficult by both the uncoupler-induced depression of membrane potential and the limited range of dependence of the H+/O ratio on the membrane potential. We have selected conditions, i.e. incubation of mitochondria at low temperatures, where the extent of non-linearity is markedly increased. It appears that the nature of the resting respiration of mitochondria in vitro is markedly dependent on the temperature: at low temperatures the percentage of resting respiration due to membrane leak decreases and that due to intrinsic uncoupling of the proton pumps increases.
• Bioblast editor: Gnaiger E
Labels: MiParea: Respiration
Organism: Rat Tissue;cell: Liver Preparation: Isolated mitochondria
Regulation: Coupling efficiency;uncoupling, Flux control, mt-Membrane potential, Temperature Coupling state: LEAK Pathway: S