β-Galactosidase from Bifidobacterium bifidum was used to catalyze the transfer of β-D-galactopyranosyl from 4-nitrophenyl-D-galactopyranoside to a hydroxyl group of 2-acetamido-2-deoxy-galactopyranose and 3-O-methyl-D-glucopyranose in the synthesis of Gal(β 1-4)GlcNAc, Gal(β 1-6)GlcNAc and Gal(β 1-6)3-O-Me-Glc in triethyl phosphate buffered solution. When 2-acetamido-2-deoxy-galactopyranose was used as acceptor the 1-4 linked disaccharide was the major product. However, when 3-O-methyl-D-glucopyranose was used as acceptor the 1-6 linked disaccharide was exclusively produced. Even blocking of the C-6 hydroxyl group with acetyl group could not change the regioselectivity of β-galactosidase from Bifidobacterium bifidum when 3-O-methyl-D-glucopyranose was used as the acceptor.
In addition, immobilized β-galactosidase (B. bifidum) on nylon powder 6 was stable and could be used repeatedly for the synthetic work.
Bifidobacterium bifidum 유래의 β-galactosidase를 이용하여 4-nitrophenyl-β-D-galactopyranoside에서 β-D-galactopyranosyl 그룹을 2-acetamido-2-deoxy-galactopyranose와 3-O-methyl-glucopranose의 OH기에 옮겨주는 반응을 triethyl phosphate라는 유기용매가 첨가된 buffer에서 수행하여 Gal(β 1-4)GlcNAc, Gal(β 1-6)GlcNAc, 그리고 Gal(β 1-6)3-O-Me-Glc을 합성하였다. N-아세틸 글루코사민에 갈락토스를 옮겨주는 반응에서는 1-4 결합으로 연결되는 이당류인 N-아세틸 락토사민이 주로 만들어졌으나, 3-O-메틸 글루코스에 갈락토스를 옮겨 줄 때는 1-6결합으로 이루어진 3-O-메틸 알로락토스만 만들어졌다. 또한 3-O-메틸 글루코스의 6번 탄소의 OH기를 아세틸로 막아서 여기에 갈락토스를 옮길 수 없도록 하였더니 갈락토스를 4번 탄소의 OH기에 옮기지 않고 아예 반응이 일어나지 않았다.
β-Galactosidase를 나일론 가루에 고정화하였더니 매우 안정하였고 여러 번 사용하여 좋은 효율의 합성반응을 수행할 수 있었다.
