High-yield synthesis of N-acetyllactosamine by regioselective transglycosylation.

The synthesis of N-acetyllactosamine (D-Galp beta 1-4D-GlcpNAc) with very low contamination of its isomer N-acetyllactosamine (D-Galp beta 1-6D-GlcpNAc) was obtained by use of regioselective transglycosylation activity of beta-galactosidase from Bacillus circulans using lactose as the donor of D-Galp and D-GlcpNAc as the acceptor. The reaction was conducted at 15 degrees C and at pH 5.0. The incubation time was considerably reduced and the yield improved 100% with respect to the best results so far described in the literature.