Sinha B A, Smejtek P
J Membr Biol. 1983;71(1-2):119-30. doi: 10.1007/BF01870680.
The physical effects of 3-phenylindole, an antimicrobial compound which interacts with phospholipids, on ion transport across phosphatidylcholine-cholesterol bilayers have been investigated using three lipophilic ions and one ion-carrier complex. It was found that 3-phenylindole increased membrane electrical conductance of positively charged membrane probes and decreased electrical conductance of negatively charged probes. The enhancement of conductance detected by nonactin-K+ complex and tetraphenylarsonium+ was several orders of magnitude, whereas the suppression of conductance due to tetraphenylborate- and dipicrylamine- was less than a factor of ten. Presence of 3-phenylindole in aqueous phase slightly decreased adsorption of tetraphenylborate- and dipicrylamine- at the membrane surface. From the voltage dependence of the steady-state conductance it was shown that 3-phenylindole induced kinetic limitation of membrane transport of potassium mediated by nonactin. No such limitation was found in the case of tetraphenylarsonium+ transport. These results are shown to be consistent with the present concept of ion diffusion in membranes and the assumption that 3-phenylindole decreases the electric potential in the membrane interior. The asymmetry of the effect of 3-phenylindole on the magnitude of conductance changes for positively and negatively charged membrane permeable ions is also discussed as a reflection of the discreteness of both the absorbed 3-phenylindole and lipid dipoles.
3-苯基吲哚是一种能与磷脂相互作用的抗菌化合物，利用三种亲脂性离子和一种离子载体复合物，研究了其对磷脂酰胆碱-胆固醇双层膜离子转运的物理效应。研究发现，3-苯基吲哚增加了带正电膜探针的膜电导，降低了带负电探针的电导。由缬氨霉素-K⁺复合物和四苯基砷鎓⁺检测到的电导增强达几个数量级，而由四苯基硼酸盐⁻和二硝基苯甲酰胺⁻导致的电导抑制小于10倍。水相中3-苯基吲哚的存在略微降低了四苯基硼酸盐⁻和二硝基苯甲酰胺⁻在膜表面的吸附。从稳态电导的电压依赖性可知，3-苯基吲哚诱导了缬氨霉素介导的钾离子膜转运的动力学限制。在四苯基砷鎓⁺转运的情况下未发现这种限制。这些结果表明与目前关于膜中离子扩散的概念以及3-苯基吲哚降低膜内部电势的假设一致。还讨论了3-苯基吲哚对带正电和带负电的膜可渗透离子电导变化幅度影响的不对称性，作为吸附的3-苯基吲哚和脂质偶极子离散性的反映。
