Van Bruggen J T, Boyett J D, van Bueren A L, Galey W R
J Gen Physiol. 1974 Jun;63(6):639-56. doi: 10.1085/jgp.63.6.639.
Our previous studies on solute drag on frog skin and synthetic heteropore membranes have been extended to a synthetic homopore membrane. The 150-A radius pores of this membrane are formed by irradiation and etching of polycarbonate films. The membrane is 6-microm thick and it has 6 x 10(8) pores cm(-2). In this study, sucrose has been used as the driver solute with bulk flow blocked by hydrostatic pressure. As before on heteroporous membranes, the transmembrane asymmetry of tracer solute is dependent on the concentration of the driver solute. Tracer sucrose shows no solute drag while maltotriose shows appreciable solute drag at 1.5 M sucrose. With tracer inulin and dextran, solute drag is detectable at 0.5 M sucrose. These results are in keeping with the previous findings on heteropore membranes. Transmembrane solute drag is the result of kinetic and frictional interaction of the driver and tracer solutes as the driver flows down its concentration gradient. The magnitude of the tracer flux asymmetry is also dependent on the size of the transmembrane pores.
我们之前对蛙皮和合成异孔膜上溶质拖曳的研究已扩展至合成同孔膜。该膜半径为150埃的孔是通过对聚碳酸酯薄膜进行辐照和蚀刻形成的。膜厚6微米，每平方厘米有6×10⁸个孔。在本研究中，蔗糖被用作驱动溶质，通过静水压力阻止总体流动。与之前在异孔膜上的情况一样，示踪溶质的跨膜不对称性取决于驱动溶质的浓度。示踪蔗糖未显示溶质拖曳，而麦芽三糖在1.5 M蔗糖浓度下显示出明显的溶质拖曳。对于示踪菊粉和右旋糖酐，在0.5 M蔗糖浓度下可检测到溶质拖曳。这些结果与之前在异孔膜上的发现一致。跨膜溶质拖曳是驱动溶质沿其浓度梯度流动时，驱动溶质与示踪溶质之间动力学和摩擦相互作用的结果。示踪通量不对称性的大小也取决于跨膜孔的尺寸。
