电喷雾串联质谱图的叠合与多肽序列分析

利用离子阱电喷雾串联质谱仪，在选择性改变某些食品参数的条件下对模式分子Met-脑啡肽和自行固相化学合成的7肽及其修饰产物、10肽和20肽进行碎裂处理，从而获得一系列具有一定差异的串联质谱图。选择具有适当互补性的图谱进行叠合处理，得到具有连贯性“三联套”（triplet）及“二联套”（doublet）碎片离子峰的叠合串联质谱图，据此可以方便准确地角析出多肽的氨基酸序列。实验结果表明，这种方法在多肽的质谱法测定中具有一定的实用性。

Superimposition and Analysis of ESI Tandem Mass Spectra

Methionine enkephalin and four synthetic peptides (a heptapeptide and its modified form, a decapeptide and an icosapeptide) were fragmented using ESI tandem mass spectrometry with certain varying instrumental parameters, such as amplitude of excitation, to produce a series of MS/MS spectra. Using the Bruker DataAnalysis software, some complementary MS/MS spectra were chosen to form a superimposed MS/MS spectrum with consecutive triplets (as well as a few doublets) consisting of product ions A n B n C n or X n Y n Z n . The amino acid sequences of the peptides were easily and accurately determined from the superimposed MS/MS spectrum, suggesting that the method is easy and suitable for peptide sequencing by tandem mass spectrometry.