Elgavish G A, Elgavish A
Biochem Biophys Res Commun. 1985 Apr 30;128(2):746-53. doi: 10.1016/0006-291x(85)90110-x.
A fast Na+-exchange is shown to be present in isolated renal brush border membranes. The lower limit of the rate constant for this process, calculated from the 23Na-NMR spectrum is 580 sec-1. The actual exchange rate may be higher. A fast 7Li exchange is also shown to be present in the isolated membrane vesicles. The characteristic overshoot of the Na+ dependent D-glucose cotransport and Na+/H+ antiport can be demonstrated. The fact that neither treatment with papain, nor lowering of the temperature to 5 degrees C affected the 23Na-NMR spectra obtained in the renal brush border membrane vesicles is consistent with the possibility that the fast Na+-exchange occurs through a channel mechanism.
研究表明，在分离出的肾刷状缘膜中存在快速的钠交换。根据23Na-NMR光谱计算，该过程速率常数的下限为580秒-1。实际交换速率可能更高。在分离出的膜囊泡中也显示存在快速的锂交换。可以证明钠依赖性D-葡萄糖共转运和钠/氢反向转运的特征性过冲。用木瓜蛋白酶处理或温度降至5摄氏度均未影响在肾刷状缘膜囊泡中获得的23Na-NMR光谱，这一事实与快速钠交换通过通道机制发生的可能性一致。
