Miyamoto Y, Balkovetz D F, Leibach F H, Mahesh V B, Ganapathy V
Department of Cell and Molecular Biology, Medical College of Georgia, Augusta 30912-2100.
FEBS Lett. 1988 Apr 11;231(1):263-7. doi: 10.1016/0014-5793(88)80744-0.
Uptake of taurine in human placental brush-border membrane vesicles was greatly stimulated in the presence of an inwardly-directed Na+ + Cl- -gradient and uphill transport of taurine could be demonstrated under these conditions. Na+ as well as Cl- were obligatory for this uptake and both ion gradients could energize the uphill transport. This Na+ + Cl- -gradient-dependent taurine uptake was stimulated by an inside-negative membrane potential, demonstrating the electrogenicity of the process. The uptake system was highly specific for beta-amino acids and the Km of the system for taurine was 6.5 +/- 0.4 microM.
在存在内向性Na⁺ + Cl⁻梯度的情况下，人胎盘刷状缘膜囊泡对牛磺酸的摄取受到极大刺激，并且在这些条件下可以证明牛磺酸的上坡转运。Na⁺以及Cl⁻对于这种摄取是必需的，并且两个离子梯度都可以为上坡转运提供能量。这种依赖于Na⁺ + Cl⁻梯度的牛磺酸摄取受到膜内负电位的刺激，证明了该过程的电生性。摄取系统对β-氨基酸具有高度特异性，该系统对牛磺酸的Km为6.5±0.4微摩尔。
