CHARACTERIZATION OF MINOR TETRA-SACCHARIDES TO HEPTA-SACCHARIDES O-LINKED TO HUMAN MECONIUM GLYCOPROTEINS BY TLC-MS MICROSEQUENCING OF NEOGLYCOLIPID DERIVATIVES IN CONJUNCTION WITH CONVENTIONAL MS AND H-1-NMR SPECTROSCOPY

As part of the establishment of a data base for core and backbone sequences of O-linked oligosaccharides of human meconium glycoproteins, the minor tetra- to hepta-saccharides released by mild-acid treatment of blood group H-active glycoproteins have been studied. These oligosaccharides are heterogeneous and difficult to isolate, and a t.l.c.-m.s. microsequencing procedure has been applied to the neoglycolipid derivatives, in conjunction with H-1-n.m.r. spectroscopy, methylation analysis, and mass spectrometry (m.s.) of native and methylated oligosaccharides. Among an array of oligosaccharides characterised are those having the branched beta-GlcNAc-(1 --> 6)[beta-Gal-(1 --> 3)]-GalNAcol core, and others with the following linear sequences not characterised previously from this source: beta-Gal-(1 --> 3)-beta-GlcNAc-(1 --> 3)-beta-Gal-(1 --> 3)-GalNAcol, beta-Gal-(1 --> 4)-beta-GlcNAc-(1 --> 3)-beta-Gal-(1 --> 3)-GalNAcol, alpha-GalNAc-(1 --> 3)-beta-Gal-(1 --> 3/4)-beta-GlcNAc-(1 --> 3?? )-GalNAcol, beta-GlcNAc-(1 --> 3)-beta-Gal-(1 --> 3/4)-beta-GlcNAc-(1 --> 3)-GalNAcol, beta-Gal-(1 --> 3/4)-beta-GlcNAc-(1 --> 3)-beta-Gal-(1 --> 3/4)-beta-GlcNAc-(1 --> 3)-beta-Gal-(1 --> 3)-GalNAcol, and beta-GlcNAc-(1 --> 3)-beta-Gal-(1 --> 3/4)-beta-GlcNAc-(1 --> 3)-beta-Gal-(1 --> 3/4)-beta-GlcNAc-(1 --> 3)-GalNAcol.