Cooperative effect of factors governing molecular ion yields in desorption/ionization mass spectrometry
Cooperative effect of factors governing molecular ion yields in desorption/ionization mass spectrometry
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DOI：
10.1002/rcm.2316
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发表时间：
2006-01-01
影响因子：
2
通讯作者：
Takayama, M
中科院分区：
文献类型：
--
作者：
Nishikaze, T;Takayama, M
利用快原子轰击（FAB）和基质辅助激光解吸/电离（MALDI）质谱（MS）研究了氨基酸和多肽分子离子产率的影响因素。在FAB条件下质子化氨基酸的离子产率取决于氨基酸的质子亲和力（PA）、疏水性和芳香性。PA和疏水性都有助于离子产率的增加，而芳香性有助于降低。在MALDI中，除赖氨酸外，氨基酸的离子产额随PA的增加而线性增加。在用肽进行的FAB和MALDI实验中，精氨酸残基的存在对于产生丰富的质子化肽是必需的。在FAB中，脂肪族和疏水性氨基酸（亮氨酸和异亮氨酸）的存在增加质子化肽的离子产率，而一些亲水性氨基酸（天冬氨酸和天冬酰胺）降低离子产率。在FAB中，两个或更多个精氨酸残基的存在不会产生更高的离子产率。在MALDI中，芳香族氨基酸（苯丙氨酸和酪氨酸）的存在增强了质子化肽的信号。因此，单个氨基酸的物理化学因素协同影响质子化氨基酸和肽的离子产率。在FAB和MALDI中，这些控制离子产率的因素影响两个过程，解吸和电离，这两个过程可以独立地考虑。版权所有（c）2005年约翰威利父子有限公司。
Factors governing the molecular ion yields of amino acids and peptides have been studied using fast atom bombardment (FAB) and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) in positive-ion mode. The ion yields of protonated amino acids under FAB conditions are dependent on proton affinity (PA), hydrophobicity, and aromaticity of amino acids. Both PA and hydrophobicity contribute to an increase in the ion yields, while aromaticity contributes to a decrease. In MALDI, the ion yields increase linearly with the increase of PA of amino acids with the exception of lysine. In both FAB and MALDI experiments with peptides, the presence of arginine residues is essential for producing abundant protonated peptides. In FAB, the presence of aliphatic and hydrophobic amino acids (leucine and isoleucine) increases the ion yields of protonated peptides, while some hydrophilic amino acids (aspartic acid and asparagines) decrease the ion yields. The presence of two or more arginine residues does not give higher ion yields in FAB. In MALDI, the presence of aromatic amino acids (phenylalanine and tyrosine) enhances the signals for protonated peptides. Thus, physicochemical factors of individual amino acids cooperatively affect the ion yields of protonated amino acids and peptides. These factors governing the ion yields in FAB and MALDI affect two processes, desorption and ionization, that can be considered independently. Copyright (c) 2005 John Wiley & Sons, Ltd.