Isolation and characterization by electrospray-ionization mass spectrometry and high-performance anion-exchange chromatography of oligosaccharides derived from hyaluronic acid by hyaluronate lyase digestion: observation of some heretofore unobserved oligosaccharides that contain an odd number of units.

Hyaluronic acid was degraded with hyaluronate lyase (E.C. 4.2.2.1, from Streptomyces hyalurolyticus), and the resulting oligosaccharides up to dp 16 were characterized by electrospray-ionization mass spectrometry (ESIMS) and high-performance anion-exchange chromatography (HPAEC) with pulsed amperometric detection (PAD). In accordance with the known regiospecificity of the enzyme, the products included even-numbered oligosaccharides of structure beta-D-4en-thrHexpA-(1-->3)-[beta-D-GlcpNAc-(1-->4)-beta-D- GlcpA]n-(1-->3)-D-GlcpNAc. Minor amounts of novel and unexpected odd-numbered oligomers, having the structure beta-D-4en-thrHexpA-(1-->3)-[beta-D-GlcpNAc-(1-->4)-D-Glc pA]n, were also isolated and characterized. This study, in addition to others beginning to appear in the literature, demonstrates the usefulness of ESIMS and HPAEC-PAD in the analysis and characterization of anionic glycosaminoglycan-type oligosaccharides.