Roseman M A, Holloway P W, Calabro M A, Thompson T E
J Biol Chem. 1977 Jul 25;252(14):4842-9.
Detergent-extracted cytochrome b5, which binds readily to phosphatidylcholine vesicles, has been shown to exchange between vesicles by the following experiments. When preformed cytochrome b5-vesicle complexes are incubated with fresh vesicles a new species arises which sediments in the analytical ultracentrifuge with a rate intermediate between those of the original components. When the same mixture is subjected to free boundary electrophoresis no slow moving component corresponding to pure vesicles is seen. The results of sucrose density gradient centrifugation are also consistent with the conclusion that cytochrome b5 exchanges between vesicles. The possibility that the above results were produced by vesicle fusion or aggregation was eliminated by light-scattering studies and a direct assay for vesicle fusion. The ability of cytochrome b5 to exchange between lipid structures has important implications not only in the cytochrome b5-lipid system but also in enzymatic reactions in which cytochrome b5 is involved.
已通过以下实验表明，经去污剂提取的细胞色素b5能与磷脂酰胆碱囊泡迅速结合，并在囊泡之间进行交换。当预先形成的细胞色素b5 - 囊泡复合物与新鲜囊泡一起孵育时，会出现一种新的物质，它在分析超速离心机中的沉降速率介于原始组分之间。当对相同混合物进行自由界面电泳时，未观察到对应于纯囊泡的缓慢移动组分。蔗糖密度梯度离心的结果也与细胞色素b5在囊泡之间交换的结论一致。通过光散射研究和囊泡融合的直接测定，排除了上述结果是由囊泡融合或聚集产生的可能性。细胞色素b5在脂质结构之间进行交换的能力不仅在细胞色素b5 - 脂质系统中，而且在涉及细胞色素b5的酶促反应中都具有重要意义。
