α-d-Glcp-(1↔1)-β-d-Galp-containing oligosaccharides, novel products from lactose by the action of β-galactosidase

A mixture of oligosaccharides produced by β-galactosidase using lactose as a substrate was fractionated according to degree of polymerization using gel filtration, followed by high-pH anion-exchange chromatography. The fractions obtained were analyzed using monosaccharide analysis, methylation analysis, mass spectrometry, and NMR spectroscopy. Twelve novel non-reducing oligosaccharides were characterized, namely, [β-d-Galp-(1→4)]n-α-d-Glcp-(1↔1)-β-d-Galp[-(4←1)-β-d-Galp]m, with n, m=(1, 2, 3, or 4) and β-d-Galp-(1→2)-α-d-Glcp-(1↔1)-β-d-Galp.