Proton leak

Hafher, R.P., Brown, G.C.. Brand, M.D. (1990). Analysis of the control of respiration rate, phosphorylation rate, proton leak rate and proton motive force in isolated mitochondria using the top-down approach of metabolic control theory. Eur. J. Biochem. 188,313-319. 

STATE 4 VERSUS STATE 3 IN VITRO PROTON LEAK... 

A first key fact (see Brand, 1995, 1997 Rolfe and Brown, 1997) is that in isolated mitochondria, this proton leak is readily demonstrable in state 4 (all requirements for mitochondrial metabolism present except ADP) but the leak is mainly abolished, or at least, becomes harder to demonstrate on transition to state 3 (ADP-... 

A second important feature worth emphasizing is that the proton leak is affected by the lipid composition of the inner mitochondrial membrane. In general, the fatty acyl chains of phospholipid components of membranes can vary in their degree of unsaturation. The proton leak increases with the incorporation of polyunsaturated fatty acids (FAs) the greater the number of double bonds, the greater the proton leak (Hulbert and Else, 2000). As we shall note in the chapter on temperature relations, fatty acyl composition of membranes, including the inner mitochondrial membranes, changes in various... 

Robin, E.D., B.J. Murphy, and J. Theodore (1984). Coordinate regulation of glycolysis by hypoxia in mammalian cells. J. Cell. Physiol. 118 287-290. Rolfe, D.F., and G.C. Brown (1997). Cellular energy utilization and molecular origin of standard metabolic rate in mammals. Physiol. Rev. 77 731-758. Rolfe, D.F., J.M. Newman, J.A. Buckingham, M.G. Clark, and M.D. Brand (1999). Contribution of mitochondrial proton leak to respiration rate in... 

Figure 7.34. Allometric relationship of mitochondrial proton leak and body mass. Proton leak measured at a potential of 170 mV is expressed per unit volume (ji ) of mitochondrial matrix. Numbers refer to the following species (1) mouse, (2) hamster, (3) rat, (4) ferret, (5) Dutch rabbit, (6) New Zealand rabbit, (7) sheep, (8) pig, and (9) horse. (Figure modified after Porter et al. 1996.)...

Porter, R.K., A.J. Hulbert, and M.D. Brand (1996). Allometry of mitochondrial proton leak influence of membrane surface area and fatty acid composition. Am. J. Physiol. 271 (Regulatory Integrative Comp. Physiol. 40) R1550-R1560. 

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