Solution additives that desalt protein ions in native mass spectrometry.
Solution additives that desalt protein ions in native mass spectrometry.
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DOI：
10.1021/ac301629s
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发表时间：
2012-09-04
影响因子：
7.4
通讯作者：
Williams, Evan R.
中科院分区：
文献类型：
--
作者：
Flick, Tawnya G.;Cassou, Catherine A.;Chang, Terrence M.;Williams, Evan R.
许多盐（如氯化钠）的存在会降低整体分子离子丰度，并将任何给定电荷状态的信号分布成许多带有不同数量加合物的阳离子形式，从而对用于分析蛋白质和蛋白质复合物的天然电喷雾电离质谱的性能产生不利影响。几种溶液添加剂，如溴化铵、碘化铵和NaSbF6，可以显著降低钠离子对蛋白质和蛋白质复合物分子离子的内聚程度。对于泛素，在同样含有1.0 mM NaCl的水溶液中加入25 mM溴化铵或碘化铵，与不添加这些添加剂时相比，完全质子化分子离子的相对丰度分别增加了72倍和56倍。这种方法减少钠离子内合的有效性与阴离子的低质子亲和（PA）值有关。极低PA的阴离子也有作为酸性分子加合的倾向，但这些加合物可以很容易地从分子离子中解离，要么在源中激活，要么随后在质谱仪中通过碰撞激活。这种减少钠离子内聚到蛋白质上的方法简单，不需要实验修改，使其成为在质谱分析之前脱盐蛋白质的其他方法的有吸引力的替代方法。
The presence of many salts, such as sodium chloride, can adversely affect the performance of native electrospray ionization mass spectrometry for the analysis of proteins and protein complexes by reducing the overall molecular ion abundances and distributing signal for any given charge state into many cationized forms with various numbers of adducts attached. Several solution additives, such as ammonium bromide, ammonium iodide, and NaSbF6, can significantly lower the extent of sodium ion adduction to the molecular ions of proteins and protein complexes. For ubiquitin, addition of 25 mM ammonium bromide or ammonium iodide into aqueous solutions also containing 1.0 mM NaCl results in a factor of 72 and 56 increase, respectively, in the relative abundances of the fully protonated molecular ions compared to when these additives are not present. The effectiveness of this method for reducing sodium ion adduction is related to the low proton affinity (PA) values of the anions. Anions with very low PA also have a propensity to adduct as an acid molecule, but these adducts can be readily dissociated from the molecular ions either by activation in the source or subsequently by collisional activation in the mass spectrometer. This method of reducing sodium ion adduction to proteins is simple and requires no experimental modifications, making it an attractive alternative to other methods for desalting proteins prior to mass spectrometry analysis.
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影响因子：
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