A new technique distinguishing alpha 2-3 sialyl linkage from alpha 2-6 linkage in sialyllactoses and sialyl-N-acetyllactosamines by post-source decayfragmentation method of MALDI-TOF mass spectrometry

alpha 2-3 and alpha 2-6 sialyl linkage types of sialyllactoses and sialyl-N -acetyllactosamines were analyzed by post-source decay (PSD) fragmentation method using matrix-assisted laser desorption/ionization time-of-flight (MA LDI-TOF) mass spectrometry. A new matrix of norharmane was suited for the M ALDI-TOF measurements of sialyl oligosaccharides. The fragment ions B-1 pro duced by the cleavage of alpha 2-3 sialyl linkages indicate much higher int ensity than those produced by the cleavage of alpha 2-6 sialyl linkages in sialyllactoses and sialyl-N-acetyllactosamines. Thus, alpha 2-3 sialyl link ages cleave much easier than alpha 2-6 sialyl linkages in MALDI-PSD fragmen tation method. These results suggest that the new techniques using PSD frag mentation of MALDI-TOF mass spectrometry enables us to distinguish alpha 2- 3 sialyl linkage from alpha 2-6 linkage in sialyl oligosaccharides.