Kleinfeld A M, Dragsten P, Klausner R D, Pjura W J, Matayoshi E D
Biochim Biophys Acta. 1981 Dec 7;649(2):471-80. doi: 10.1016/0005-2736(81)90438-7.
An investigation has been carried out of the relationship between changes in the fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) and concomitant changes in the lateral diffusion of proteins and lipid probes in membranes. Plasma membranes from lymphocytes and a CH1 mouse lymphoma line were treated with up to 70 mol% (relative to the total membrane phospholipid) of oleic or linoleic fatty acids. Under these conditions the fluorescence polarization of DPH decreased by between 8 and 15% which, in the framework of the microviscosity approach, suggests a membrane fluidity change of between 20 and 50%. The lateral diffusion coefficients of surface immunoglobin and the lipid probes 3,3'-dioctadecylindocarbocyanine and pyrene were also measured in these membranes using the fluorescence photobleaching recovery technique and the rate of pyrene excimer formation. The diffusion rates were found to be unaffected by the presence of free fatty acids. Hence despite large 'microviscosity' changes as reported by depolarization of DPH fluorescence, lateral diffusion coefficients are essentially unchanged. This finding is consistent with the idea that perturbing agents such as free fatty acids do not cause a general fluidization of the membrane but act locally to alter, for example, protein function. It is also consistent with the suggestion that lateral mobility of membrane proteins is not modulated by the lipid viscosity.
对1,6 - 二苯基 - 1,3,5 - 己三烯（DPH）荧光偏振变化与膜中蛋白质和脂质探针横向扩散的伴随变化之间的关系进行了研究。用高达70摩尔%（相对于总膜磷脂）的油酸或亚油酸处理淋巴细胞和CH1小鼠淋巴瘤系的质膜。在这些条件下，DPH的荧光偏振降低了8%至15%，在微粘度方法的框架内，这表明膜流动性变化在20%至50%之间。还使用荧光光漂白恢复技术和芘激基缔合物形成速率在这些膜中测量了表面免疫球蛋白以及脂质探针3,3'-二辛基吲哚碳菁和芘的横向扩散系数。发现扩散速率不受游离脂肪酸存在的影响。因此，尽管DPH荧光去极化报告了较大的“微粘度”变化，但横向扩散系数基本不变。这一发现与游离脂肪酸等扰动剂不会导致膜的普遍流化而是局部作用以改变例如蛋白质功能的观点一致。这也与膜蛋白的横向流动性不受脂质粘度调节的观点一致。
