Effect of ATP, EDTA and EGTA on the simultaneous binding of Na, K, Mg and Ca by rat liver microsomes
Effect of ATP, EDTA and EGTA on the simultaneous binding of Na, K, Mg and Ca by rat liver microsomes
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ATP、EDTA和EGTA对大鼠肝微粒体同时结合Na、K、Mg和Ca的影响
DOI：
10.1002/jcp.1040690104
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发表时间：
1967
影响因子：
5.6
通讯作者：
N. Pace
中科院分区：
文献类型：
--
作者：
H. Sanui;N. Pace
在生理pH值的Na，K，Mg和Ca的存在下，络合剂可以影响大鼠肝微粒体的阳离子结合的方式并不总是容易预测的，简单地从个人的形成常数的知识。增加浓度（0至20 mM）的强非生物络合剂，乙二胺四乙酸（EDTA），产生了急剧下降，几乎为零的结合钙，增加到一个高的平台结合钠和钾和初始增加，然后急剧减少结合镁。增加EDTA的钙偏好类似物乙二醇二甘醇的浓度（β-氨基乙基醚）四乙酸酯（EGTA）产生类似的变化，除了结合的Mg增加并保持升高，表明该试剂在生理pH下非常弱地络合Mg。生物络合剂三磷酸腺苷（ATP），在约4°C和pH 6.4下，引起结合Mg和Ca的逐渐直线和平行减少以及结合Na和K的伴随和平行增加。然而，EDTA和EGTA的结果表明，在不同的条件下，ATP可能会增强二价阳离子的结合。这种性质的反应可能是ATP刺激的亚细胞颗粒的二价阳离子摄取的意义。
In the presence of Na, K, Mg and Ca at physiological pH, complexing agents can affect cation binding by rat liver microsomes in a manner not always readily predictable simply from a knowledge of individual formation constants. Increasing concentrations (0 to 20 mM) of the strong nonbiological complexing agent, ethylenediaminetetraacetate (EDTA), produced a sharp decrease almost to zero in bound Ca, an increase to a high plateau in bound Na and K and an initial increase followed by a sharp decrease in bound Mg. Increasing concentrations of the Ca‐preferring analogue of EDTA, ethylene bisglycol (β‐aminoethylether) tetraacetate (EGTA), produced similar changes except that bound Mg increased and remained elevated, indicating that this agent complexes Mg very weakly at physiological pH. The biological complexing agent, adenosine triphosphate (ATP), caused a gradual rectilinear and parallel decrease in bound Mg and Ca and a concomitant and parellel increase in bound Na and K at about 4°C and pH 6.4. Results with EDTA and EGTA suggest, however, that under different conditions, enhancement by ATP of divalent cation binding may be possible. Reactions of this nature may be of significance in ATP stimulated divalent cation uptake by subcellular particles.