Relating electrospray ionization response to nonpolar character of small peptides
Relating electrospray ionization response to nonpolar character of small peptides
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DOI：
10.1021/ac9914869
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发表时间：
2000-07-01
影响因子：
7.4
通讯作者：
Enke, CG
中科院分区：
文献类型：
--
作者：
Cech, NB;Enke, CG
生物分子中的非极性区域被研究作为控制其电喷雾电离（ESI）质谱响应的决定性因素。反应进行了比较的一系列肽的C-末端残基是不同的氨基酸与越来越多的非极性侧链。对于具有更广泛的非极性区域的肽，观察到增加的ESI响应。通过比较不同氨基酸残基的非极性表面积和转移吉布斯自由能的值来检查这种增加的基础。与十八胺的响应比较也作出了，观察到这种高度表面活性的离子在ESI响应中胜过所有其他分析物。这些观察结果在平衡分配模型的基础上得到了合理化，该模型已成功用于拟合几个双分析物系统在整个浓度范围内的实验数据。该模型表明，由于ESI液滴表面存在过量电荷，因此分析物对液滴表面的相对亲和力决定了其相对ESI响应。增加的非极性特征，这导致增强的亲和力的表面相，结果在更成功的竞争过量的电荷和更高的ESI响应。
Nonpolar regions in biological molecules are investigated as a determining factor governing their electrospray ionization (ESI) mass spectrometric response. Response is compared for a series of peptides whose C-terminal residue is varied among amino acids with increasingly nonpolar side chains. Increased ESI response is observed for peptides with more extensive nonpolar regions. The basis for this increase is examined by comparing values of nonpolar surface area and Gibbs free energy of transfer for the different amino acid residues. Comparisons of response with octadecylamine are also made, and this highly surface-active ion is observed to outcompete all other analytes in ESI response. These observations are rationalized on the basis of the equilibrium partitioning model, which is used successfully to fit experimental data throughout the concentration range for several two-analyte systems. This model suggests that because excess charge exists on ESI droplet surfaces, an analyte's relative affinity for the droplet surface determines its relative ESI response. Increased nonpolar character, which leads to enhanced affinity for the surface phase, results in more successful competition for excess charge and higher ESI response.