SEQUENCE-SPECIFIC FRAGMENTATION OF MATRIX-ASSISTED LASER-DESORBED PROTEIN PEPTIDE IONS
SEQUENCE-SPECIFIC FRAGMENTATION OF MATRIX-ASSISTED LASER-DESORBED PROTEIN PEPTIDE IONS
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DOI：
10.1021/ac00117a027
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发表时间：
1995-11-01
影响因子：
7.4
通讯作者：
LENNON, JJ
中科院分区：
文献类型：
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作者：
BROWN, RS;LENNON, JJ
通过利用基质辅助激光解吸/电离 (MALDI) 技术产生的离子的延迟脉冲离子提取，在线性飞行时间质谱仪的离子源中观察到肽和蛋白质分析物的快速 (< 320 ns) 亚稳态离子碎片。小肽（例如牛胰岛素的氧化 B 链）在肽残基之间的酰胺连接键处表现出断裂。重叠序列信息由肽的 C 端和 N 端（c(n)-、y(n)- 和 z(n)* 型碎片离子）的碎片提供。在有利的情况下，较大的蛋白质还可以表现出丰富的序列特异性碎片离子。细胞色素 c 就是一个例子，它在沿着蛋白质氨基酸主链的酰胺键处发生大量（大约 80%）快速断裂。仅观察到从 C 末端（c(n) 片段）开始的酰胺键裂解。观察到的碎片模式为这些分子提供了大量的潜在序列信息。完整质子化分子离子的外部质量校准被证明具有通常在 100 ppm 左右的质量精度。根据已知序列，观察到的碎片离子的质量精度范围为 +/- 0.20 Da（所研究的较小肽（即牛胰岛素的氧化 B 链））和 +/- 0.38 Da（所研究的最大蛋白质（细胞色素 c））。
By utilizing delayed pulsed ion extraction of ions generated via the matrix-assisted laser desorption/ionization (MALDI) technique, fast (< 320 ns) metastable ion fragmentation is observed for both peptide and protein analytes in the ion source of a linear time-of-flight mass spectrometer. Small peptides such as the oxidized B chain of bovine insulin exhibit fragmentation at the amide linking bond between peptide residues. Overlapping sequence information is provided by fragmentation from both the C- and N-terminal ends of the peptide (c(n)-, y(n)-, and z(n)*-type fragment ions). Larger proteins can also exhibit a wealth of sequence specific fragment ions in favorable cases. One example is cytochrome c, which undergoes substantial (similar to 80%) fast fragmentation at the amide bonds along the amino acid backbone of the protein. Only amide bond cleavages initiating from the C-terminal end (c(n) fragments) are observed. The observed fragmentation pattern provides a significant amount of potential sequence information for these molecules. External mass calibration of the intact protonated molecular ions is demonstrated with mass accuracies typically around 100 ppm. Mass accuracies for the observed fragment ions ranged from +/- 0.20 Da for the smaller peptides studied (i.e,, oxidized B chain of bovine insulin) to +/- 0.38 Da for the largest protein studied (cytochrome c), based upon the known sequences.