Le Grimellec C, Giocondi M C, Carrière B, Carrière S, Cardinal J
Am J Physiol. 1982 Mar;242(3):F246-53. doi: 10.1152/ajprenal.1982.242.3.F246.
The physical state of membrane lipids and relationships with the activity of Na+-K+-ATPase and alkaline phosphatase were studied in basolateral and brush border membranes of the dog kidney. Fluorescence polarization and electron spin resonance experiments demonstrate that basolateral membranes are much more fluid than brush border membranes. This can be accounted for by a difference in fluidity of the lipid part of the membranes. Broad (43-17 degrees C) thermotropic transitions are observed in liposomes made from total lipid extracts of brush border and basolateral membranes. Fluorescence data strongly suggest that thermotropic transitions also occur in intact membranes and that a change in membrane physical state may take place around the physiological temperature. A nonlinear Arrhenius plot for the Na+-K+-ATPase activity in basolateral membranes (breakpoint 21 degrees C) provides additional support for the existence of a lipid liquid leads to gel transition in antiluminal plasma membranes. A break in the Arrhenius plot of alkaline phosphatase activity is also observed but at a temperature significantly higher (26 degrees C) than that of the end of the thermotropic transition. "Room temperature" appears as a critical zone for lipid physical state and activities of both enzymes.
对犬肾基底外侧膜和刷状缘膜中膜脂的物理状态及其与钠钾ATP酶和碱性磷酸酶活性的关系进行了研究。荧光偏振和电子自旋共振实验表明，基底外侧膜比刷状缘膜的流动性大得多。这可以用膜脂质部分流动性的差异来解释。在用刷状缘膜和基底外侧膜的总脂质提取物制备的脂质体中观察到宽泛的（43 - 17℃）热致转变。荧光数据有力地表明，完整膜中也发生热致转变，并且在生理温度附近可能发生膜物理状态的变化。基底外侧膜中钠钾ATP酶活性的非线性阿伦尼乌斯图（转折点21℃）为反腔质膜中存在脂质液相到凝胶相的转变提供了额外支持。碱性磷酸酶活性的阿伦尼乌斯图中也观察到一个断点，但温度（26℃）明显高于热致转变结束时的温度。“室温”似乎是脂质物理状态和两种酶活性的关键区域。
