Tandem MS can distinguish hyaluronic acid from N-acetylheparosan

Abstract

Isobaric oligosaccharides enzymatically prepared from hyaluronic acid (HA) and N-acetylheparosan (NAH), were distinguished using tandem mass spectrometry. The only difference between the two series of oligosaccharides was the linkage pattern (in HA 1→3 and in NAH 1→4) between glucuronic acid and N-acetylglucosamine residues. Tandem mass spectrometry afforded spectra in which glycosidic cleavage fragment ions were observed for both HA and NAH oligosaccharides. Cross-ring cleavage ions ^0,2A_n and ^0,2A_n-h (n is even number) were observed only in GlcNAc residues of NAH oligosaccharides. One exception was an ^0,2A₂ ion fragment observed for the disaccharide from HA. These cross-ring cleavage fragment ions are useful to definitively distinguish HA and NAH oligosaccharides.