PROTON AND HYDROXIDE ION PERMEABILITY OF PHOSPHOLIPID-VESICLES
PROTON AND HYDROXIDE ION PERMEABILITY OF PHOSPHOLIPID-VESICLES
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DOI：
10.1073/pnas.78.7.4324
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发表时间：
1981-01-01
期刊：
影响因子：
--
通讯作者：
TANFORD, C
中科院分区：
文献类型：
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作者：
NOZAKI, Y;TANFORD, C
H+通过磷脂双分子层的表观渗透性是通过测量H+从具有内部缓冲空间的大单层磷脂囊泡流出来确定的。得到的值是。apprx。在室温下10-9 cm/s，比最近报道的H+和OH-的联合渗透率低5个数量级[Nichols等，（1980）]。用这种方法测量的表观渗透率是溶液中与阴离子平衡的H+和不带电物质（HCl或HNO3）的运动贡献的总和。有证据表明，不带电的物质占主导地位，H+本身的渗透系数不大于5。10 - 12 cm / s。通过使用pH值为10的缓冲囊泡来测量OH-渗透性的尝试并没有给出一个结论性的结果，因为囊泡壁似乎在暴露于这个pH值时被破坏了。未损伤膜估计为10-7 cm/s。
The apparent permeability of H+ through phospholipid bilayers was determined by measuring H+ efflux from large unilamellar phospholipid vesicles with internal space buffered at pH 4. The value obtained is .apprx. 10-9 cm/s at room temperature, 5 orders of magnitude lower than was recently reported for the combined permeability for H+ and OH- [Nichols et al, (1980)]. The apparent permeability measured in this way is the sum of contributions from the movement of H+ and of uncharged species (HCl or HNO3) in equilibrium with anions in the solution. There is evidence that the uncharged species make the dominant contribution and that the permeability coefficient for H+ per se is no larger than 5 .times. 10-12 cm/s. An attempt to measure OH- permeability by use of vesicles buffered at pH 10 did not give a conclusive result because the vesicle walls appeared to be damaged by exposure to this pH. An apparent permeability coefficient of .apprx. 10-7 cm/s was estimated for undamaged membranes.