Thiol-dependent passive K+-Cl- transport in sheep red blood cells. V. Dependence on metabolism.
Thiol-dependent passive K+-Cl- transport in sheep red blood cells. V. Dependence on metabolism.
复制标题
绵羊红细胞中硫醇依赖性被动 K-Cl- 转运。
DOI：
10.1152/ajpcell.1983.245.5.c445
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发表时间：
1983
期刊：
影响因子：
--
通讯作者：
Lauf,PK
中科院分区：
文献类型：
--
作者：
Lauf,PK
在低K+绵羊红细胞中，通过人工改变细胞ATP水平，测量哇巴因不敏感的K+流出和Rb+内流，发现在ATP浓度高于0.5mM的细胞中，N-乙基马来酰亚胺（NEM）激活了Cl-依赖的K+转运。培养4 h后，NEM完全抑制了K+-Cl-转运，但不降低基础Cl-依赖的K+通量。在含有葡萄糖、肌苷和无机磷酸盐的培养基中通过第二次孵育补充细胞ATP时，NEM刺激的K+（Rb+）通量再次出现。流量再激活的幅度直接和单调变化的ATP水平。这些数据构成了第一个明确的证据，可逆的ATP依赖性的巯基功能上参与巯基依赖性K+-Cl-转运蛋白，这表明巯基依赖性和体积敏感性K+-Cl-转运系统是不同的操作。
Measurement of ouabain-insensitive K+ efflux and Rb+ influx in low-K+ sheep red blood cells with artificially altered cellular ATP levels revealed that Cl--dependent K+ transport was activated by N-ethylmaleimide (NEM) in cells with ATP concentrations above 0.5 mM. Depletion of ATP by starvation at 37 degrees C either in glucose-free media for 16 h or in 2-deoxy-D-glucose-containing media for 4 h completely abolished the response of K+-Cl-transport to NEM but did not reduce the basal Cl--dependent K+ flux. On repletion of cellular ATP by a second incubation in media containing glucose, inosine, and inorganic phosphate, the NEM-stimulated K+ (Rb+) flux reappeared. The magnitude of flux reactivation varied directly and monotonically with the ATP level. The data constitute the first unequivocal evidence for a reversible ATP dependence of thiol groups functionally involved in the thiol-dependent K+-Cl- transporter, suggesting that thiol-dependent and volume-sensitive K+-Cl- transport systems are operationally different.