Novel proteoglycan linkage tetrasaccharides of human urinary soluble thrombomodulin, SO4-3GlcAβ1-3Galβ1-3 (±Siaα2-6)Galβ1-4Xyl

Abstract

O-linked sugar chains with xylose as a reducing end linked to human urinary soluble thrombomodulin were studied. Sugar chains were liberated by hydrazinolysis followed by N-acetylation and tagged with 2-aminopyridine. Two fractions containing pyridylaminated Xyl as a reducing end were collected. Their structures were determined by partial acid hydrolysis, two-dimensional sugar mapping combined with exoglycosidase digestions, methylation analysis, mass spectrometry, and NMR as SO4-3GlcAβ1-3Galβ1-3(±Siaα2-6)Galβ1- 4Xyl. These sugar chains could bind to an HNK-1 monoclonal antibody. This is believed to be the first example of a proteoglycan linkage tetrasaccharide with glucuronic acid 3-sulfate and sialic acid.