PROTON HYDROXIDE PERMEABILITY OF LIPOSOMES
PROTON HYDROXIDE PERMEABILITY OF LIPOSOMES
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DOI：
10.1073/pnas.80.1.165
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发表时间：
1983-01-01
期刊：
影响因子：
--
通讯作者：
NICHOLS, JW
中科院分区：
文献类型：
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作者：
DEAMER, DW;NICHOLS, JW
在先前研究中产生极值的2种条件下比较了脂质体渗透性与净质子-氢氧化物通量。在第一，小的pH梯度被允许衰减接近pH 7和渗透系数在10-4厘米/秒的范围内获得。在第二，大pH梯度的衰减速率（approxeq.2）。3个pH单位），并报告了10-9 cm/s范围内的表观渗透系数。重复后一项研究的条件，大pH梯度的衰减产生了限制净质子-氢氧化物通量的扩散势。因此，从通量计算的渗透系数被低估，并不反映固有的质子渗透性。在小梯度衰减使得扩散电势可以忽略的条件下，使用相同的脂质体制剂，测得的渗透系数接近10-4 cm/s，如前所述。
Liposome permeability to net proton-hydroxide flux was compared under 2 conditions that have produced extreme values in previous studies. In the 1st, small pH gradients were permitted to decay near pH 7 and permeability coefficients in the range of 10-4 cm/s were obtained. In the 2nd, the decay rate of large pH gradients (.apprxeq. 3 pH units) was measured and apparent permeability coefficients in the range of 10-9 cm/s were reported. The conditions of the latter study were repeated and the decay of large pH gradients produced a diffusion potential that limited net proton-hydroxide flux. The permeability coefficients calculated from the flux are therefore underestimated and do not reflect intrinsic proton permeability. With the same liposome preparations under conditions in which small gradients decay so that diffusion potentials are negligible, the measured permeability coefficient is near 10-4 cm/s, as reported earlier.