Backer J M, Dawidowicz E A
Biochemistry. 1981 Jun 23;20(13):3805-10. doi: 10.1021/bi00516a021.
The kinetics of cholesterol exchange between two populations of small unilamellar vesicles has been investigated. There is no change in the initial rate of this exchange process over a 100-fold change in the acceptor vesicle concentration at a constant donor concentration. These results are not consistent with a collision-dependent exchange mechanism. In support of transfer via the aqueous phase, the inclusion of a negatively charged lipid into the vesicles did not affect the exchange rate. Evidence for a water-soluble pool of cholesterol that had partitioned ut of the vesicle was obtained. Finally, cholesterol exchange was observed when donor and acceptor membranes were separated by a barrier through which neither could pass. These data together support our contention that the exchange of cholesterol between these vesicles involves a water-soluble intermediate.
已经研究了两群小单层囊泡之间胆固醇交换的动力学。在供体浓度恒定的情况下，受体囊泡浓度变化100倍时，该交换过程的初始速率没有变化。这些结果与碰撞依赖的交换机制不一致。为了支持通过水相进行转移，向囊泡中加入带负电荷的脂质并不影响交换速率。获得了胆固醇从囊泡中分配出来形成水溶性池的证据。最后，当供体膜和受体膜被一个两者都无法通过的屏障隔开时，观察到了胆固醇交换。这些数据共同支持了我们的观点，即这些囊泡之间的胆固醇交换涉及一种水溶性中间体。
