Anion/anion exchange in human neutrophils.
Anion/anion exchange in human neutrophils.
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人类嗜中性粒细胞中的阴离子/阴离子交换。
DOI：
10.1085/jgp.88.2.195
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发表时间：
1986-08
期刊：
影响因子：
--
通讯作者：
De Weer P
中科院分区：
文献类型：
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作者：
Simchowitz L;Ratzlaff R;De Weer P
总单向氯通量（约1.4毫当量/升细胞水X分钟）在稳态人多形核白细胞沐浴在148 mM的氯介质中，约70%的行为作为自我交换介导的非选择性阴离子载体，不抑制二苯乙烯二磺酸盐。研究了这种载体介导的交换的五种性质：相对于作为外部Cl浓度的函数的36 Cl流入，观察到底物饱和[对于正常Cl细胞，当Cl取代对氨基马尿酸盐（PAH）时，表观Km（Cl）约为22 mM，当Cl取代葡萄糖醛酸盐时，表观Km（Cl）约为5 mM]，以及关于36 Cl流出作为内部Cl替代PAH的浓度的函数[对于浸泡在148 mM Cl中的细胞，表观Km（Cl）等于35 mM];内Cl对36 Cl内流有反式刺激作用（代替PAH），表观Km（Cl）等于35 mM，和36 Cl流出的外部Cl与表观Km（Cl）一致，为22 mM（Cl替代PAH）或约5 mM（Cl取代葡萄糖醛酸）; Cl和PAH之间存在底物竞争，但载体似乎对葡萄糖醛酸缺乏亲和力;由载体介导的流入和流出受到细胞外α-氰基-4-羟基肉桂酸酯（CHC）的竞争性抑制，表观Ki在Cl培养基中等于9 mM或在PAH培养基中约为1 mM（抑制剂本身的转运非常缓慢）;内部氯与外部氯或多环芳烃发生1：1的反向转运，对CHC敏感。一个简单的平衡竞争模型，提出了所有的细胞外配体的相互作用，为正常的Cl细胞。对于细胞外Cl、PAH和CHC，载体的真实米氏常数的最小二乘值分别为5.03 +/- 0.83、50.3 +/- 14.9和0.29 +/- 0.09 mM。
Of the total one-way chloride fluxes (approximately 1.4 meq/liter cell water X min) in steady state human polymorphonuclear leukocytes bathed in 148 mM Cl media, approximately 70% behaves as self-exchange mediated by a nonselective anion carrier that is not inhibited by stilbene disulfonates. Five properties of this carrier-mediated exchange were investigated: substrate saturation is seen with respect to 36Cl influx as a function of the external Cl concentration [for normal-Cl cells, the apparent Km(Cl) is approximately 22 mM when Cl replaces para-amino- hippurate (PAH) and approximately 5 mM when Cl replaces glucuronate], and with respect to 36Cl efflux as a function of the concentration of internal Cl replacing PAH [apparent Km(Cl) congruent to 35 mM for cells bathed in 148 mM Cl]; there is trans stimulation of 36Cl influx by internal Cl (replacing PAH) with an apparent Km(Cl) congruent to 35 mM, and of 36Cl efflux by external Cl with an apparent Km(Cl) congruent to 22 mM (Cl replacing PAH) or approximately 5 mM (Cl replacing glucuronate); there is substrate competition between Cl and PAH, but the carrier appears devoid of affinity for glucuronate; influxes and effluxes mediated by the carrier are subject to competitive inhibition by extracellular alpha-cyano-4-hydroxycinnamate (CHC), with an apparent Ki congruent to 9 mM in Cl medium or approximately 1 mM in PAH medium (transport of the inhibitor itself is very slow); and internal Cl and external Cl or PAH undergo 1:1 countertransport, which is CHC sensitive. A simple equilibrium-competition model is proposed that accounts for all the extracellular ligand interactions presented for normal-Cl cells. Least-squares values of the carrier's true Michaelis constants for extracellular Cl, PAH, and CHC are 5.03 +/- 0.83, 50.3 +/- 14.9, and 0.29 +/- 0.09 mM, respectively.