Engelke M, Tähti H, Vaalavirta L
Institute of Experimental Physics, University of Bremen, Box 330440, 28334 Bremen, Germany.
Toxicol In Vitro. 1996 Apr;10(2):111-5. doi: 10.1016/0887-2333(95)00103-4.
Aliphatic, alicyclic and aromatic hydrocarbons interact with biological membranes. Until now little has been known about their mode of interaction with the membrane bilayer and membrane integral proteins with toxic effects to cells. The lipid theory hypothesis explains the toxic effects by the organic solvent-induced disorder in the lipid bilayer, which indirectly affects the function of membrane-embedded proteins. The extent of bilayer perturbations is ascribed to the solvent accumulation in the bilayer, which is related only to the lipophilicity of the molecule, independent of the chemical structure. In this study the fluidizing effects of aliphatic, alicyclic and aromatic hydrocarbons were compared. Membrane fluidity changes were estimated from the pyrene excimer formation, using pyrene and pyrene derivatives to label specifically the localization of solvent molecules in the transverse plane of the bilayer. Liposomal, microsomal and synaptosomal membrane preparations were evaluated because proteins and cholesterol, as natural membrane components, increase the bilayer order and reduce the organic solvent membrane/buffer partition. In the concentration range investigated, only the aromatic solvents disorder the lipid bilayer, with the greatest perturbation in the centre of the bilayer. These results are related to structural properties of the organic solvents investigated.
脂肪族、脂环族和芳香族碳氢化合物与生物膜相互作用。到目前为止，人们对它们与膜双层以及对细胞有毒性作用的膜整合蛋白的相互作用方式了解甚少。脂质理论假说认为，有机溶剂会导致脂质双层紊乱，从而间接影响膜嵌入蛋白的功能，以此来解释毒性作用。双层扰动的程度归因于双层中溶剂的积累，这仅与分子的亲脂性有关，与化学结构无关。在本研究中，比较了脂肪族、脂环族和芳香族碳氢化合物的流化作用。使用芘和芘衍生物特异性标记双层横向平面中溶剂分子的定位，通过芘激基缔合物的形成来估计膜流动性的变化。对脂质体、微粒体和突触体膜制剂进行了评估，因为蛋白质和胆固醇作为天然膜成分，会增加双层的有序性并降低有机溶剂在膜/缓冲液中的分配。在所研究的浓度范围内，只有芳香族溶剂会扰乱脂质双层，在双层中心的扰动最大。这些结果与所研究有机溶剂的结构特性有关。
