Thomas P D, Podder S K
Biochim Biophys Acta. 1982 Jun 14;688(2):453-9. doi: 10.1016/0005-2736(82)90356-x.
Two simple chemical methods are described for the determination of the transbilayer distribution of gangliosides GD1a and GM1 in phosphatidylcholine vesicles. The data presented here show an increase in the percentage of GD1a exposed on the outer surface of vesicles with increasing mole fraction of GD1a. The percentage of GD1a exposed on 1:50 and 1:5 GD1a-dipalmitoylphosphatidylcholine vesicles were found to be 67% and 83%, respectively. The same trend is seen for vesicles with dimyristoylphosphatidylcholine and distearoylphosphatidylcholine. Extrapolation of the data to infinite dilution gives 65% of GD1a exposed on the surface of GD1a-dipalmitoylphosphatidylcholine vesicles. The results indicate that composition-dependent changes in transbilayer distribution of GD1a can only partly account for the observed increase in the reactivity of GD1a in vesicles towards neuraminidase from clostridium perfringens as the ratio of GD1a to phosphatidylcholine increases.
本文描述了两种简单的化学方法，用于测定神经节苷脂GD1a和GM1在磷脂酰胆碱囊泡中的跨膜分布。此处呈现的数据表明，随着GD1a摩尔分数的增加，暴露于囊泡外表面的GD1a百分比也会增加。发现在1:50和1:5的GD1a-二棕榈酰磷脂酰胆碱囊泡上暴露的GD1a百分比分别为67%和83%。对于含有二肉豆蔻酰磷脂酰胆碱和二硬脂酰磷脂酰胆碱的囊泡，也观察到了相同的趋势。将数据外推至无限稀释时，发现GD1a-二棕榈酰磷脂酰胆碱囊泡表面有65% 的GD1a暴露。结果表明，随着GD1a与磷脂酰胆碱的比例增加，GD1a跨膜分布的组成依赖性变化只能部分解释观察到的囊泡中GD1a对产气荚膜梭菌神经氨酸酶反应性增加的现象。
