乙酰化蛋白的质谱鉴定研究

报道了两种生物质谱技术ESI-MS和MALDI-MS在鉴定乙酰化修饰蛋白BSA-ac中的应用研究结果. 乙酰化修饰蛋白通过特征碎裂峰m/z 126.1或MS/MS质谱图中相差一个赖氨酸的相邻b或y离子之间170 Da分子量的差异确证赖氨酸乙酰化修饰, 并且后者提供具体修饰位点信息. 研究提示ESI-MS和MALDI-MS两种质谱技术均可用于鉴定实际复杂样品中的乙酰化蛋白, 且在乙酰化蛋白的鉴定中各有其优点.

Identification of Acetylated Proteins by Mass Spectrometry

Identification of acetylated proteins was performed via identifying BSA-ac by two kinds of mass spectrometers including ESI-MS and MALDI-MS. The lysine-acetylated proteins can be confirmed from the observation of a specific ion at m/z 126.1 or a mass difference of 170 Da between the adjacent b-ions or y-ions. The LTQ-Orbitrap hybrid spectrometer(ESI-MS) comprising an LC pre-concentration system and an ESI ionization source could acquire much more information than the others. However,the ion at m/z 126.1 could not be detected with a linear ion trap analyzer,which was well observed through a 4700 Proteomic analyzer(MALDI-TOF-TOF). This diagnostic ion can also reduce the false positive rate. It has been demonstrated that ESI and MALDI MS are complementary to each other in analyzing acetylated proteins. Accordingly,it can be concluded from the fact that different results would be obtained with different mass spectrometers,and matched protocols should be used for the identification of the acetylated proteins.