大鼠心肌线粒体内、外膜磷脂动态结构的研究

THE STUDY OF DYNAMIC MICROSTRUCTURE OF MITOCHONDRIAL OUTER AND INNER MEMBRANES PHOSPHOLIPID FROM RAT MYOCARDIUM

我们以DPH为荧光探针.用毫微秒荧光分光光度计测定了大鼠心肌线粒体及线粒体内、外膜的动态微细结构;用HPLC分析了磷脂组成.实验结果提示.完整线粒体膜流动性主要反映了线粒体外膜的运动状态.线粒体内膜微粘度及磷脂分子摇动角大于外膜,扩散速率小于外膜.除去了蛋白质的线粒体内、外膜磷脂脂质体膜流动性无明显差异.提示线粒体内膜的高微粘度与膜中所含有的多量蛋白有关.

The viscosity of the phospholipid bilayer and the wobbling angle of the phospholipid molecules of outer and inner membranes from rat cardiac mitochondria were measured with a nanosecond time-resolved fluorometer using a fluorophore, 1,6 - diphenyl - 1,3,5 -hexatriene (DPH). Measurements were also made on liposomes prepared by lipids extracted from each membrane. Phospholipid constituents in membranes were analysed by HPLC. Results showed that membrane viscosity and wobbling angle of phospholipids of outer membrane fluidity of mitochondria mainly reflected the motion state of outer mitochondrial membrane. The inner membranes showed a high or viscosity and lower rotational diffussion constant of phospholipids as compared with outer membranes. The liposomes prepared from lipid extracts of outer and inner membranes showed a lower viscosity and/or higher wobbling angle of phospholipids as compared with the membranes themselves. These results suggest that the limitation of molecular motion of phospholipids by membrane proteins results in an increase in the average viscosity and the microdynamic values obtained in the inner membrane fraction reflect the interacion between phospholipid and protein which is abundant in the inner membrane.