LIPOSOMES WITH A LARGE TRAPPING CAPACITY PREPARED BY FREEZING AND THAWING OF SONICATED PHOSPHOLIPID MIXTURES
LIPOSOMES WITH A LARGE TRAPPING CAPACITY PREPARED BY FREEZING AND THAWING OF SONICATED PHOSPHOLIPID MIXTURES
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DOI：
10.1016/0003-9861(81)90358-1
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发表时间：
1981-01-01
影响因子：
3.9
通讯作者：
PICK, U
中科院分区：
文献类型：
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作者：
PICK, U
描述了一种葡萄糖转运蛋白的重构程序，该程序基于超声磷脂混合物与溶解蛋白的快速冷冻，然后解冻和短暂的超声。通过这种简单的程序制备的脂质体，被称为冷冻-解冻-超声程序，具有10 μ m的特定捕获体积。l H2O/mg磷脂，最大捕获效率为25-30%的溶液，包括离子，小有机分子或蛋白质。通过这种技术形成的大脂质体，可能是由超声脂质体融合的结果，通过增加介质的离子强度、蔗糖和增加脂质体浓度来强烈抑制。冷冻-解冻-超声处理对从大豆中获得的粗磷脂提取物或磷脂酰胆碱与带负电荷的磷脂（磷脂酰丝氨酸）或带正电荷的脂质（十六烷基三甲基溴化铵）的混合物有效，但对纯磷脂酰胆碱脂质体无效。在快速冷冻过程中，水分子可能不得不在带电荷的磷脂界面上结晶，以便使聚变过程发生。通过冷冻-解冻-超声法制备的脂质体对质子、阳离子和阴离子的渗透性低，这使其成为离子传输研究的有用系统。给出了几个离子载体介导的离子转运反应的例子，这些反应引起了脂质体内质子和钙离子的积累。
A reconstitution procedure for a glucose-transporting protein based on a rapid freezing of sonicated phospholipid mixtures with the solubilized protein followed by thawing and a brief sonication has been described. The liposomes prepared by this simple procedure, referred to as the freezing-thawing-sonication procedure, have a specific trapping volume of 10 .mu.l H2O/mg phospholipid and a maximal trapping efficiency of 25-30% of the solution including ions, small organic molecules or proteins. Formation of large liposomes by this technique, which probably results from fusion of sonicated liposome, is strongly inhibited by increasing the ionic strength of the medium, by sucrose and by increasing the liposome concentration. The freezing-thawing-sonication procedure is effective with a crude phospholipid extract obtained from soybeans or with mixtures of phosphatidylcholine with either a negatively charged phospholipid (phosphatidylserine) or a positively charged lipid (cetyltrimethylammonium bromide) but not with pure phosphatidylcholine liposomes. Water molecules may have to crystallize on the charged phospholipid interface during the rapid freezing in order to allow the fusion process to take place. Liposomes prepared by the freezing-thawing-sonication procedure have a low permeability to protons, cations and anions which makes them a useful system for studies of ion transport. A few examples of ionophore-mediated ion transport reactions which give rise to accumulation of protons and Ca ions inside the liposomes are given.