Olsnes S, Sandvig K
J Biol Chem. 1986 Feb 5;261(4):1542-52.
In sodium-free buffer of low ionic strength, the uptake of chloride and sulfate in Vero cells was found to occur mainly by antiport which was very sensitive to inhibition by 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid. Efflux of anions from the cells appeared to energize the uptake. While the uptake of Cl- occurred over a wide pH range, that of SO4(2-) showed a clear maximum at pH 6-7. The rate of efflux of 36Cl- and 35SO4(2-) was strongly increased by the presence of permeant anions in the efflux buffer. Preincubation of the cells at slightly alkaline pH strongly increased the rate of C1- efflux into buffers nominally free of permeant anions, as well as the efflux by exchange. This increase did not occur if the cells were depleted for ATP during the preincubation. Depolarization of the cells reduced the rate of efflux into buffers without permeant anions, indicating that the efflux is at least partly due to net, electrogenic, anion transport. The efflux by antiport was not affected by manipulations of the membrane potential, indicating electroneutral exchange. The uptake and efflux were increased to the same extent with increasing temperature, the activation energies were Ea = 25 kcal/mol of Cl- and Ea = 12 kcal/mol of SO4(2-). Similar anion antiport appears to occur in L, baby hamster kidney, and HeLa S3 cells.
在低离子强度的无钠缓冲液中，发现Vero细胞对氯离子和硫酸根离子的摄取主要通过反向转运进行，这种反向转运对4-乙酰氨基-4'-异硫氰基芪-2,2'-二磺酸的抑制非常敏感。细胞中阴离子的外流似乎为摄取提供了能量。虽然氯离子的摄取在较宽的pH范围内发生，但硫酸根离子（SO4(2-)）的摄取在pH 6 - 7时出现明显的最大值。外流缓冲液中存在渗透性阴离子会强烈增加36Cl-和35SO4(2-)的外流速率。将细胞在略碱性pH下预孵育会强烈增加氯离子外流到名义上不含渗透性阴离子的缓冲液中的速率，以及通过交换的外流速率。如果在预孵育期间细胞耗尽ATP，则不会出现这种增加。细胞去极化会降低氯离子外流到没有渗透性阴离子的缓冲液中的速率，这表明外流至少部分是由于净的、电生的阴离子转运。通过反向转运的外流不受膜电位操作的影响，表明是电中性交换。随着温度升高，摄取和外流以相同程度增加，氯离子的活化能为Ea = 25 kcal/mol，硫酸根离子（SO4(2-)）的活化能为Ea = 12 kcal/mol。类似的阴离子反向转运似乎也存在于L细胞、幼仓鼠肾细胞和HeLa S3细胞中。
