Endogenous L-glutamate transport in oocytes of Xenopus laevis.
Endogenous L-glutamate transport in oocytes of Xenopus laevis.
复制标题
DOI：
10.1016/0005-2736(91)90244-3
复制
发表时间：
1991-07
期刊：
影响因子：
--
通讯作者：
Jürgen Steffgen;Hermann Koepsell;Wolfgang Schwarz
中科院分区：
文献类型：
--
作者：
Jürgen Steffgen;Hermann Koepsell;Wolfgang Schwarz
在非洲爪蟾卵母细胞中存在一种内源性的Na+-谷氨酸协同转运蛋白。转运蛋白不接受谷氨酸作为底物。对底物的依赖性表现出两种饱和组分，对l-谷氨酸具有低亲和力（K1/2= 9mM）和高亲和力（K1/2= 0.35 μM）。对外部Na+的依赖性表现出饱和组分，aK 1/2值约为5 mM，以及未饱和至110 mM Na+的组分。在电压钳位卵母细胞中，可以证明Na+依赖性谷氨酸转运直接与Rb+的反向转运相耦合。的Na+，K+-dependentl-谷氨酸摄取的电压依赖性的分析表明，正电荷在运输周期中向内移动。
The existence of an endogenous Na+-glutamate cotransporter in the oocytes ofXenopus laevisis demonstrated. The transporter does not acceptd-glutamate as substrate. The dependence on substrate displays two saturating components with low (K1/2= 9mM) and high (K1/2= 0.35 μM) affinities forl-glutamate. The dependence on external Na+exhibits a saturating component with aK1/2value of about 5 mM and a component that has not saturated up to 110 mM Na+. In voltage-clamped oocytes, it is possible to demonstrate that Na+-dependentl-glutamate transport is directly coupled to countertransport of Rb+. The analysis of the voltage dependence of the Na+, K+-dependentl-glutamate uptake suggests that positive charges are moved inwardly during the transport cycle.