Solubility of L-cystine in NaCl and artificial urine solutions
Solubility of L-cystine in NaCl and artificial urine solutions
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DOI：
10.1007/s007060050004
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发表时间：
2000-01-01
影响因子：
1.8
通讯作者：
Königsberger, LC
中科院分区：
文献类型：
--
作者：
Königsberger, E;Wang, ZH;Königsberger, LC
l -胱氨酸是天然存在的氨基酸中最难溶的，由遗传疾病引起的胱氨酸结石占所有尿路结石的1-4%。由于尿中胱氨酸的浓度是与结石形成有关的唯一因素，因此对胱氨酸在尿中的溶解度有适当的了解是必要的。一些研究小组已经报道了l -胱氨酸的溶解度，但结果是分散的。在这项工作中，对胱氨酸在尿石症最相关的条件下的溶解度进行了系统的调查。l -胱氨酸的溶解度在25.0℃和37.0℃，pH值从1到9，在不同的介质中测量，包括(i) 0.300 mol.dm(-3) NaCl溶液和（ii）人工尿液溶液。采用联合专家分类系统（Joint Expert Speciation System， JESS）计算机软件包和文献报道的胱氨酸质子化常数对胱氨酸的溶解度进行建模。实验测定的溶解度数据与计算机模拟的胱氨酸溶解度结果非常吻合。本研究结果表明，无机组分的存在对胱氨酸在尿中的溶解度影响不大。
L-Cystine is the least soluble of the naturally occurring amino acids, and cystine stones, caused by a genetic disorder, account for between 1-4% of all urinary stones. Since the concentration of cystine in urine is the only factor related to the stone formation, a proper knowledge of cystine solubility in urine is necessary. Some research groups have already reported on the solubility of L-cystine, but the results are scattering. In this work, a systematic investigation of cystine solubility under conditions most pertinent to urolithiasis was carried out. The solubilities of L-cystine were measured at 25.0 and 37.0 degrees C, from pH 1 to 9, and in different media including (i) 0.300 mol.dm(-3) NaCl solution and (ii) artificial urine solutions. The Joint Expert Speciation System (JESS) computer package and selected protonation constants of cystine reported in literature were used to model the solubilities of cystine. Excellent agreement was obtained between the experimentally determined solubility data and computer modelling of cystine solubility. The results of this work show that the presence of inorganic components has little influence on the solubility of cystine in urine.