高粱根质膜K~+通道蛋白的溶解及重组

SOLUBILIZATION AND RECONSTITUTION OF THE K￣+ CHANNEL PROTEIN FROM PLASMA MEMBRANE OF SORGHUM VULGARE Pers. ROOT CELLS

用水两相法纯化的高粱根质膜嵌入平面脂双层膜，可以测得离子通道电流。记录了典型的单离子通道。ＴｒｉｔｏｎＸ—１００使质膜蛋白溶解，除去不溶物后，加入ＡｍｂｅｒｌｉｔｅＸＡＤ—２使膜蛋白重组为蛋白脂质体。将蛋白脂质体嵌入脂双层，测定了脂双层上Ｋ＋通道电流逐渐出现的过程，该典型的通道电流记录的通道电导为１１２ｐＳ。通过改变前后槽ＫＣｌ浓度，测定蛋白脂质体嵌入脂双层后的稳态电流一电压关系，近似计算稳态逆转电位，由ＧＨＫ等式得Ｋ＋和Ｃｌ－的选择通透比Ｐｋ：Ｐｃｌ为８．６主要是通透Ｋ＋。关键词：

The plasma membrane of Sorghum root cells purified with apueous two-phase partition method was incorporated into planar bilayer lipid membrane. Ion channel currents were measured. Typical single channel current was recorded. Plasma membrane proteins were solubilized with Triton X-100 and unsolubilized materials were discarded. The solubilizedprotein was reconstituted into proteoliposome.The formation process of ion channel current was recoded after incorporation of proteoliposome into bilayer. The conductance of typical channel was 112pS. The relation of stable membrancurrent and membranepotential was measurred by changing KCl concentrations in cis and trans chamber. The revereal potential was caculated according to the Ⅰ-Ⅴ relation and the ion-selectivity of the channel was calulated by GHK equation. Pk.Pcl=8.6. So the channel was banly permeable to K+.