Complexation of iron(III) and iron(II) by citrate.: Implications for iron speciation in blood plasma
Complexation of iron(III) and iron(II) by citrate.: Implications for iron speciation in blood plasma
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DOI：
10.1016/s0162-0134(99)00222-6
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发表时间：
2000-02-01
影响因子：
3.9
通讯作者：
Hefter, GT
中科院分区：
文献类型：
--
作者：
Königsberger, LC;Königsberger, E;Hefter, GT
铁与低分子量配体在体内的主要络合物的浓度和身份的估计是重要的，以提高目前的理解，这种微量元素的代谢。这些估计需要了解铁-柠檬酸盐络合物的稳定性。以前对Fe（III）-柠檬酸盐和Fe（II）-柠檬酸盐的平衡性质的研究不一致。因此，在这项工作中，玻璃电极电位滴定已被用来重新确定的Fe（III）和Fe（II）-柠檬酸盐系统在25 ℃，在1.00 M（Na）Cl和这些常数的可靠性进行了评估，通过比较测量和预测的氧化还原电位的三元Fe（III）-Fe（II）-柠檬酸盐系统的形成常数。以这种方式获得的形成常数被用于在血浆中的低分子量铁馏分的计算机模拟模型。因此，铁的氧化还原平衡首次被纳入大型血浆模型。这些计算的结果表明，占主导地位的铁（II）碳酸盐络合物和大量的水合铁（II）在人血浆中。(C)2000 Elsevier Science Inc. All rights reserved.
Estimates of the concentrations and identity of the predominant complexes of iron with the low-molecular-mass ligands in vivo are important to improve current understanding of the metabolism of this trace element. These estimates require a knowledge of the stability of the iron-citrate complexes. Previous studies on the equilibrium properties of the Fe(III)-citrate and Fe(II)-citrate are in disagreement. Accordingly, in this work, glass electrode potentiometric titrations have been used to re-determine the formation constants of both the Fe(III)- and Fe(II)-citrate systems at 25 degrees C in 1.00 M (Na)Cl and the reliability of these constants has been evaluated by comparing the measured and predicted redox potentials of the ternary Fe(III)-Fe(lI)-citrate system. The formation constants obtained in this way were used in computer simulation models of the low-molecular-mass iron fraction in blood plasma. Redox equilibria of iron are thus included in large models of blood plasma for the first time. The results of these calculations show the predominance of Fe(II)carbonate complexes and a significant amount of aquated Fe(II) in human blood plasma. (C) 2000 Elsevier Science Inc. All rights reserved.