Harris W R, Keen C
Department of Chemistry, University of Missouri, St. Louis 63121.
J Nutr. 1989 Nov;119(11):1677-82. doi: 10.1093/jn/119.11.1677.
During the last decade, investigators employing a wide variety of separation techniques have reported that serum albumin, rather than serum transferrin, is the major carrier protein for labile zinc. However, in contrast to these studies, a simple comparison of the zinc binding constants for albumin and transferrin suggests a significant role for transferrin with regard to serum zinc transport. In the present study multicomponent equilibrium calculations that incorporate recently determined binding constants for zinc-transferrin as well as equilibrium constants for the binding of bicarbonate, sulfate and phosphate to apotransferrin have been used to model the distribution of labile zinc in normal human serum. Anion binding has a major impact on the predicted zinc distribution, lowering the percentage of zinc bound to transferrin from 56% to 11%. The model gives approximately 1% zinc as low-molecular-weight complexes. The improved model results are in good agreement with biological studies on the distribution of zinc among serum proteins.
在过去十年中，运用多种分离技术的研究人员报告称，血清白蛋白而非血清转铁蛋白是不稳定锌的主要载体蛋白。然而，与这些研究不同的是，对白蛋白和转铁蛋白的锌结合常数进行简单比较表明，转铁蛋白在血清锌运输方面具有重要作用。在本研究中，采用了多组分平衡计算方法，该方法纳入了最近测定的锌 - 转铁蛋白结合常数以及碳酸氢根、硫酸根和磷酸根与脱铁转铁蛋白结合的平衡常数，以模拟正常人血清中不稳定锌的分布。阴离子结合对预测的锌分布有重大影响，使与转铁蛋白结合的锌百分比从56%降至11%。该模型得出约1%的锌以低分子量复合物形式存在。改进后的模型结果与关于锌在血清蛋白中分布的生物学研究结果高度吻合。
