Department of Chemistry , University of Massachusetts , Amherst , Massachusetts 01003 , United States.
ACS Appl Mater Interfaces. 2018 Nov 28;10(47):40443-40451. doi: 10.1021/acsami.8b15976. Epub 2018 Nov 15.
The analysis of low-level protein biomarkers in serum is precluded by the presence of other highly abundant serum proteins. Hence, the preliminary removal of serum albumin along with other abundant proteins in serum (i.e., immunoglobulins, transferrin, haptoglobin, α-2-macroglobulin, and apolipoproteins) is often a requirement prior to any biomarker analysis. In this work, we take advantage of the low isoelectric points (pI's) of these highly abundant proteins to selectively deplete them from serum by extraction using functionalized amphiphilic polymeric nanoassemblies. The selectivity of extraction is dependent on the pI of the protein and the extraction pH, which holds true even for extremely complex protein mixtures like serum. High extraction capacity is achieved by optimizing the extraction conditions and is found to be comparable to currently available methods for depletion. Depletion of these abundant acidic proteins allows for the enhanced detection of higher pI proteins and enables a 3 orders of magnitude increase in detection sensitivity for a putative cancer biomarker, demonstrating the utility of these polymeric assemblies for enhancing the analysis of the serum proteome.
血清中低丰度蛋白生物标志物的分析受到其他高丰度血清蛋白的限制。因此，在进行任何生物标志物分析之前，通常需要初步去除血清中的白蛋白以及其他丰富的蛋白质（即免疫球蛋白、转铁蛋白、触珠蛋白、α-2-巨球蛋白和载脂蛋白）。在这项工作中，我们利用这些高丰度蛋白的低等电点（pI），通过使用功能化两亲性聚合物纳米组装体的提取来选择性地从血清中去除它们。提取的选择性取决于蛋白质的 pI 和提取 pH，即使对于像血清这样极其复杂的蛋白质混合物也是如此。通过优化提取条件实现了高提取容量，并且发现与现有的耗竭方法相当。这些丰富的酸性蛋白的耗竭可以增强对更高 pI 蛋白的检测，并使假定的癌症生物标志物的检测灵敏度提高 3 个数量级，证明了这些聚合物组装体在增强血清蛋白质组分析方面的实用性。
