Identification and synthesis of a trisaccharide produced from lactose by transgalactosylation

Article abstract of DOI:10.1016/S0008-6215(99)00309-2

Enzymatic transgalactosylation of lactose by means of Streptococcus thermophilus, subspecies DN-001065, led to a mixture of D-galactose (~4%), D-glucose (~15%), lactose (~51%), minor disaccharides (6%), trisaccharides (~20%) and tetrasaccharides (3%). The major trisaccharide (~16%) was identified by NMR spectroscopy and chemical synthesis as being the known β-D-galactopyranosyl-(1→3)-β-D-galactopyranosyl-(1→4)-D-glucose (3'-β-D-galactopyranosyl-lactose). It was purified from a mixture of peracetylated oligosaccharides by column chromatography followed by deacetylation. For the first time, 3'-β-D-galactopyranosyl-lactose has been obtained on the 1 g scale, by resorting to simple techniques and equipment. NMR spectra have been unambiguously assigned. Copyright (C) 2000 Elsevier Science Ltd.