Cass A, Finkelstein A
J Gen Physiol. 1967 Jul;50(6):1765-84. doi: 10.1085/jgp.50.6.1765.
The osmotic permeability coefficient, P(f), and the tagged water permeability coefficient, P(d), were determined for thin (<100 A) lipid membranes formed from ox brain lipids plus DL-alpha-tocopherol; their value of approximately 1 x 10(-3) cm/sec is within the range reported for plasma membranes. It was established that P(f) = P(d). Other reports that P(f) > P(d) can be attributed to the presence of unstirred layers in the experimental determination of P(d). Thus, there is no evidence for the existence of aqueous pores in these thin phospholipid membranes. The adsorption onto the membrane of a protein that lowers its electrical resistance by a factor of 10(3) was found not to affect its water permeability; however, glucose and sucrose were found to interact with the membrane to modify P(f). Possible mechanisms of water transport across these films are discussed, together with the implications of data obtained on these structures for plasma membranes.
测定了由牛脑脂质加DL-α-生育酚形成的薄（<100埃）脂质膜的渗透渗透系数P(f)和标记水渗透系数P(d)；它们约为1×10⁻³厘米/秒的值在报道的质膜范围内。已确定P(f)=P(d)。其他关于P(f)>P(d)的报道可归因于在P(d)的实验测定中存在未搅拌层。因此，没有证据表明这些薄磷脂膜中存在水孔。发现一种能使膜电阻降低10³倍的蛋白质吸附到膜上并不影响其水渗透性；然而，发现葡萄糖和蔗糖与膜相互作用以改变P(f)。讨论了水跨这些膜运输的可能机制，以及从这些结构获得的数据对质膜的意义。
