Kubota Shintaro, Ozaki Shunsuke, Onishi Jun, Kano Kenji, Shirai Osamu
Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University,Sakyo, Kyoto 606-8502, Japan.
Anal Sci. 2009 Feb;25(2):189-93. doi: 10.2116/analsci.25.189.
Ion transport from one aqueous (W1) to another (W2) across bilayer lipid membranes (BLM) containing gramicidin A (GA) was investigated by recording current fluctuations, when various alkali metal chlorides and potassium salts were used as supporting electrolytes. The magnitude of the single-channel current at a given membrane potential depended on not only the cationic species, but also on the anionic species, and then it decreased with an increase in the diameter of the anion when the diameter of the anion was larger than the pore size of the GA channel. The baseline of the recording current, however, increased with an increase in the diameter of the anion, and its height depended on the concentration of GA in the BLM. The results indicate that GA serves as not only a channel-forming compound, but also as a carrier compound in the BLM.
当使用各种碱金属氯化物和钾盐作为支持电解质时，通过记录电流波动，研究了含有短杆菌肽A（GA）的双层脂质膜（BLM）中离子从一种水相（W1）跨膜运输到另一种水相（W2）的情况。在给定膜电位下，单通道电流的大小不仅取决于阳离子种类，还取决于阴离子种类，当阴离子直径大于GA通道孔径时，单通道电流大小会随着阴离子直径的增加而减小。然而，记录电流的基线会随着阴离子直径的增加而升高，其高度取决于BLM中GA的浓度。结果表明，GA在BLM中不仅起到形成通道的化合物的作用，还起到载体化合物的作用。
