Metastable decay of peptides and proteins in matrix‐assisted laser‐desorption mass spectrometry
Metastable decay of peptides and proteins in matrix‐assisted laser‐desorption mass spectrometry
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DOI：
10.1002/rcm.1290050412
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发表时间：
1991-04
影响因子：
2
通讯作者：
B. Spengler;D. Kirsch;R. Kaufmann;R. Cotter
中科院分区：
文献类型：
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作者：
B. Spengler;D. Kirsch;R. Kaufmann;R. Cotter
利用一台改进的LAMMA 1000反射式飞行时间（TOF）质谱仪，对基质辅助激光解吸产生的蛋白质和肽离子的碎片化进行了研究。虽然使用基质技术通常观察不到离子加速前（即在激光脉冲后几纳秒内）共价键的断裂，但在我们的仪器中可以研究较长时间尺度上的广泛碎片化。高质量分辨率（对于胰岛素和肽，M/ΔM≈1200 - 1800）通过测量在经过两级反射过程中获得的子离子的飞行时间差异，使得即使是母分子离子的微小质量损失（发生在无场漂移区的第一段）也能够被研究。已经发现这种亚稳态衰变的类型和程度在很大程度上取决于所研究的物质。典型的碎片化是氨的损失以及部分氨基酸侧链的丢失。对于所研究的大多数肽和蛋白质观察到的由于这种亚稳态碎片化而产生的大量峰，至少在一定程度上可以解释基质辅助激光解吸TOF质谱中典型的峰展宽（以及因此导致的较差质量分辨率）现象。
Fragmentation of protein and peptide ions generated by matrix-assisted laser desorption has been investigated using a modified LAMMA 1000 reflecting time-of-flight (TOF) mass spectrometer. Whereas fragmentation of covalent bonds prior to ion acceleration (i.e., within several ns after the laser pulse) in general is not observed using the matrix technique, extensive fragmentation on a longer time scale can be studied in our instrument. The high mass resolution (M/ΔM≈1200–1800 for insulin and peptides) permits the investigation of even small mass losses from parent molecular ions (occuring in the first section of the field-free drift region) by measuring flight time differences of daughter ions acquired during passage through a two-stage reflection. The kind and extent of this metastable decay has been found to depend strongly on the substance under investigation. Typical fragmentations are loss of ammonia and parts of the amino acid side-chains. The large abundances of peaks due to such metastable fragmentation, observed for most of the peptides and proteins investigated, may, at least in part, explain peak broadening (and, hence, poor mass resolution) typical in matrix-assisted laser-desorption TOF mass spectra.