Ding D H, Kaplan S
Prep Biochem. 1976;6(1):61-79. doi: 10.1080/00327487608061599.
The separation of inner and outer membrane of Rhodopseudomonas spheroides has been achieved by means of sucrose density gradient (20%, 40%, 60%, w/w) centrifugation. The upper fraction of the gradient, with a specific density 1.181 (g/cm3), is high in cytochrome and succinate dehydrogenase activities, low in lipopolysaccharides and it is designated the inner membrane fraction. The bottom fraction of the gradient, with a specific density 1.240, is high in lipopolysaccharide and contains neither cytochrome nor succinate dehydrogenase activities. This fraction is the cell wall or outer membrane fraction. The intermediate band on the gradient is an unseparated fraction of inner and outer membrane fragments. This fraction has a specific denisty of 1.211 and represents less than 3% of total crude envelope. Thin sections of the vesicles of the inner membrane fraction and those of outer membrane provide morphological evidence for the identity of the individual membrane fractions. At least 22 protein bands are resolved by employing sodium dodecyl sulfate slab gel electrophoresis. Six bands are present only in the inner membrane and two bands are found exclusively in the outer membrane. Most of the remaining polypeptides are present in greater amounts in the inner membrane relative to the outer membrane fractions.
通过蔗糖密度梯度（20%、40%、60%，w/w）离心实现了球形红假单胞菌内膜与外膜的分离。梯度上层部分的比重为1.181（g/cm³），细胞色素和琥珀酸脱氢酶活性高，脂多糖含量低，被指定为内膜部分。梯度下层部分的比重为1.240，脂多糖含量高，既不含细胞色素也无琥珀酸脱氢酶活性。该部分为细胞壁或外膜部分。梯度上的中间带是内膜和外膜片段未分离的部分。该部分的比重为1.211，占总粗包膜的比例不到3%。内膜部分和外膜部分囊泡的超薄切片为各个膜部分的一致性提供了形态学证据。采用十二烷基硫酸钠平板凝胶电泳可分辨出至少22条蛋白带。六条带仅存在于内膜中，两条带仅在外膜中发现。相对于外膜部分，大多数其余多肽在内膜中的含量更高。
