Cation transport in oxidant-stressed human erythrocytes: heightened N-ethylmaleimide activation of passive K+ influx after mild peroxidation.
Cation transport in oxidant-stressed human erythrocytes: heightened N-ethylmaleimide activation of passive K+ influx after mild peroxidation.
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氧化应激的人红细胞中的阳离子转运：轻度过氧化后 N-乙基马来酰亚胺对被动钾离子流入的激活增强。
DOI：
10.1016/0005-2736(89)90381-7
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Fairbanks,G
中科院分区：
文献类型：
--
作者：
Sheerin,HE;Snyder,LM;Fairbanks,G
在存在叠氮化物的情况下，对正常和慢性脱水（遗传性干细胞症）的人红细胞进行轻度过氧化处理（315 μM过氧化氢（H2 O2），15分钟）。随后的被动（哇巴因抗性）K+转运活动的表达通过测量86 Rb+内流来分析。正常红细胞的过氧化不影响基础K+转运活性，但0.5 mMN-乙基马来酰亚胺（NEM）引起的K+内流的增量增加了3倍。增强的K+内流是氯离子依赖性的，但只有部分抑制0.1 mM呋塞米。NEM激活后刺激活性逐渐下降，但可以通过第二次NEM治疗恢复。血红蛋白先前转化为一氧化碳形式消除了对过氧化物的反应，而200 μM丁基化羟基甲苯（BHT）仅产生部分抑制作用，表明H2 O2的作用需要活化的、不稳定的血红蛋白物质与膜的相互作用，但脂质过氧化是不够的。NEM处理后的过氧化也增强了NEM活化，表明增强不需要改变具有刺激或抑制位点的NEM反应。在遗传性干细胞症红细胞的被动K+转运不激活NEM，有或没有H2 O2预处理。结果表明，对红细胞的适度过氧化损伤可以提高转运系统的活化，该转运系统被认为能够介导表达它的细胞中的净K+流出和体积减少。细胞肿胀和其他因素是由假定的结合K+的阴离子通道（带3）分子亚群的构象变化介导的传送器
Normal and chronically dehydrated (hereditary xerocytosis) human red cells were subjected to mild peroxidative treatment (315 μM hydrogen peroxide (H2O2), 15 min) in the presence of azide. The subsequent expression of passive (ouabain-resistant) K+transport activities was analyzed by measurement of86Rb+influx. Peroxidation of normal red cells did not affect basal K+transport activity, but the increment in K+influx elicited by 0.5 mMN-ethylmaleimide (NEM) was increased 3-fold. The enhanced K+influx was chloride-dependent, but only partially inhibited by 0.1 mM furosemide. Stimulated activity declined progressively after NEM activation, but could be restored by a second NEM treatment. Prior conversion of hemoglobin to the carbonmonoxy form abolished the response to peroxide, while 200 μM butylated hydroxytoluene (BHT) exerted only partial inhibition, suggesting that the effect of H2O2requires interaction of activated, unstable hemoglobin species with the membrane, but that lipid peroxidation is not sufficient. Peroxidation following NEM treatment also enhanced NEM activation, indicating that enhancement does not require altered NEM reactions with stimulatory or inhibitory sites. Passive K+transport in hereditary xerocytosis red cells was not activated by NEM, with or without H2O2pretreatment. The results demonstrate that modest peroxidative damage to red cells can heighten the activation of a transport system that is thought to be capable of mediating net K+efflux and volume reduction in cells that express it. Models are proposed in which the effects of NEM, H2O2, cell swelling and other factors are mediated by conformational changes in a postulated subpopulation of anion channel (Band 3) molecules that bind the K+transporter.