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 oligo

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 β-d-4en-thrHexpA-(1 → 3)-[β-d-GlcpNAc-(1 → 4)-β-d-GlcpA]n-(1 → 3)-d-GlcpNAc. Minor amounts of novel and unexpected odd-numbered oligomers, having the structure β-d-4en-thrHexpA-(1 → 3)-[β-d-GlcpNAc-(1 → 4)-d-GlcpA]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.