The Proton Permeability of Liposomes Made from Mitochondrial Inner Membrane Phospholipids: Comparison with Isolated Mitochondria

阅读量：

作者：

展开

摘要：

Unilamellar liposomes with native phospholipid fatty acid composition were prepared from rat liver mitochondrial inner membrane phospholipids by extrusion in medium containing 50 m m potassium. They were diluted into low potassium medium to establish a transmembrane potassium gradient. A known membrane potential was imposed by addition of valinomycin, and proton flux into liposomes was measured. Valinomycin in the range 10 p m –1n m was sufficient to fully establish membrane potential. Valinomycin concentrations above 3 n m catalyzed additional proton flux and were avoided. At 300 p m valinomycin, proton flux depended nonlinearly on membrane potential. At 160 mV membrane potential the flux was 30 nmol H + /min/mg phospholipid—approximately 5% of the proton leak flux under comparable conditions in isolated mitochondria, indicating that leak pathways through bulk phospholipid bilayer account for only a small proportion of total mitochondrial proton leak.

展开

关键词：

Key words: Mitochondria &#8212 Vesicle &#8212 Proton leak &#8212 Phospholipid &#8212 Liposome &#8212 Fatty acid

DOI：

10.1007/s002329900168

被引量：

309

年份：

1997