State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China.
Talanta. 2012 May 15;93:239-44. doi: 10.1016/j.talanta.2012.02.024. Epub 2012 Feb 17.
Thermodynamic data such as the binding constants are vital parameters describing interactions between exotic trace compounds and biomolecules in biochemical property modeling. In this study, the stability constants of organometallic compound and protein complexes were studied by using capillary electrophoresis coupled with inductively coupled plasma mass spectrometry (CE-ICP-MS), considering its low detection limits and low sample demand. Four organotin compounds (trimethyltin (TMT), tripropyltin (TPrT), tributyltin (TBT), triphenyltin (TPhT)) and human serum albumin (HSA) were used as model organometallic compounds and protein, respectively. Affinity capillary electrophoresis (ACE) and nonequilibrium capillary electrophoresis assays of equilibrium mixtures (NECEEM) were performed and compared by using ICP-MS as the detector to determine the binding constants of organotin compounds and HSA in 1:1 molar ratio assumption. Constant measurements of the two methods were both simple, however, ACE assays were more accurate and more appropriate for the constant determination of the organotin-HSA complexes, considering the errors of the NECEEM method. A good precision of the binding constants (log K(b)) using the ACE method was proved by different mathematical calculations, and the values were 6.13 ± 0.51 (TMT), 5.72 ± 0.38 (TPrT), 5.68 ± 0.34 (TBT), 6.05 ± 0.38 (TPhT) respectively for each of the organotin-HSA complexes, showing non-covalent interaction between organotin compounds and HSA. Meanwhile, this study also confirms the suitability of CE-ICP-MS method for further studies on organometallic complexation.
热力学数据（如结合常数）是描述生化性质建模中外来痕量化合物与生物分子之间相互作用的重要参数。在这项研究中，采用毛细管电泳与电感耦合等离子体质谱（CE-ICP-MS）联用的方法，研究了有机金属化合物和蛋白质复合物的稳定常数，因为这种方法具有较低的检测限和较小的样品需求。四丁基锡（TBT）、三苯基锡（TPhT））和人血清白蛋白（HSA）分别用作模型有机金属化合物和蛋白质。采用等速电泳（ACE）和非平衡毛细管电泳法（NECEEM），并使用 ICP-MS 作为检测器进行比较，在 1:1 摩尔比假设下，确定了 TMT、TPrT、TBT 和 TPhT 与 HSA 的结合常数。两种方法的常数测量都很简单，但是考虑到 NECEEM 方法的误差，ACE 方法更准确，更适合于有机锡-HSA 配合物的常数测定。不同的数学计算证明了 ACE 方法测定结合常数（log K(b)）具有良好的精密度，对于每个有机锡-HSA 配合物，得到的值分别为 6.13±0.51（TMT）、5.72±0.38（TPrT）、5.68±0.34（TBT）和 6.05±0.38（TPhT），表明有机锡化合物与 HSA 之间存在非共价相互作用。同时，本研究还证实了 CE-ICP-MS 方法适用于进一步研究有机金属络合。
