Gangliosides from human granulocytes:: A nano-ESI QTOF mass spectrometry fucosylation study of low abundance species in complex mixtures

Nano-ESI QTOF MS was used for sensitive mapping and sequencing of single molecular species in complex ganglioside mixtures obtained from human granulocytes, where the fucosylated carbohydrate chains of granulocyte gangliosides carry sLe(x) and VIM-2 epitopes postulated to interact with E-selectin of the blood vessel wall in the early phase of the inflammation process. Functionally relevant components are expressed only at a low level, but using the negative ion detection it is possible to trace and identify such species, which were not detectable even by TLC. Advantage of the low-energy CID fragmentation for low abundance components of the complex ganglioside mixtures in the negative ion mode is to produce clear-cut series of fragment ions for sequencing. Fucosylation analysis carried out for each molecular species by MS/MS permits the clear distinction between sLe(x) and VIM-2 epitope. VIM-2 epitope was expressed in all species with a longer sugar core, while in the short oligosaccharide chain with a sLe(x) only, using biological material at a mid-femtomol level detection. (C) 2001 American Society for Mass Spectrometry.