Boudouard M, Giudicelli J, Vannier C, Sudaka P
Biochem J. 1986 Apr 1;235(1):111-6. doi: 10.1042/bj2350111.
Horse kidney brush border membrane proteins were incorporated into phosphatidylcholine vesicles. Structural analysis of proteoliposomes prepared with various lipid:protein ratios showed that: (a) only a few of the proteins present in the crude brush border extract are integrated, (b) all known membrane hydrolases are integrated, and (c) these proteoliposomes are homogeneous vesicles. Papain solubilization of brush border membrane hydrolases, i.e. aminopeptidase M, neutral alpha-glucosidase, gamma-glutamyltransferase and alkaline phosphatase, performed in parallel on native membrane vesicles and proteoliposomes, revealed similar kinetics. Analysis of membrane vesicles and proteoliposomes on sucrose density gradients either without any treatment, or after papain treatment showed that: (a) in proteoliposomes, neutral alpha-glucosidase is associated with radiolabelled phosphatidylcholine, and (b) papain-treated vesicles and proteoliposomes released enzyme activity in the same way. These results suggest that the integration mechanism of brush border membrane proteins may be similar in proteoliposomes and native membrane vesicles. Transport experiments under equilibrium exchange conditions showed that the uptake properties of proteoliposomes are similar to those of brush border membrane vesicles.
马肾刷状缘膜蛋白被整合到磷脂酰胆碱囊泡中。对用不同脂质与蛋白质比例制备的蛋白脂质体进行结构分析表明：(a) 粗刷状缘提取物中存在的蛋白质只有少数被整合，(b) 所有已知的膜水解酶都被整合，并且 (c) 这些蛋白脂质体是均匀的囊泡。在天然膜囊泡和蛋白脂质体上平行进行木瓜蛋白酶对刷状缘膜水解酶（即氨肽酶M、中性α-葡萄糖苷酶、γ-谷氨酰转移酶和碱性磷酸酶）的溶解，显示出相似的动力学。在蔗糖密度梯度上对膜囊泡和蛋白脂质体进行分析，无论是未经任何处理还是木瓜蛋白酶处理后，结果表明：(a) 在蛋白脂质体中，中性α-葡萄糖苷酶与放射性标记的磷脂酰胆碱相关联，并且 (b) 木瓜蛋白酶处理的囊泡和蛋白脂质体以相同方式释放酶活性。这些结果表明，刷状缘膜蛋白在蛋白脂质体和天然膜囊泡中的整合机制可能相似。在平衡交换条件下的转运实验表明，蛋白脂质体的摄取特性与刷状缘膜囊泡相似。
