Yoon J H, Ajisaka K
Meiji Institute of Health Science, Meiji Milk Products Co., Ltd., Odawara, Japan.
Carbohydr Res. 1996 Oct 4;292:153-63. doi: 10.1016/s0008-6215(96)91041-1.
beta-Galactosidases from four different sources were used to catalyze the transfer of beta-D-galactopyranosyl from 4-nitrophenyl-beta-D-galactopyranoside to a hydroxyl group of 2-acetamido-2-deoxy-galactopyranose in the synthesis of Gal beta (1-3)GalNAc (1), Gal beta (1-4)GalNAc (2) and Gal beta (1-6)GalNAc (3), in triethyl phosphate buffered solutions (20-60%). When beta-galactosidases from Penicillium multicolor and Aspergillus oryzae were used as the catalysts, the beta (1-6)-linked disaccharide was produced as the major product. However, with beta-galactosidase from Bifidobacterium bifidum, the major products were the beta (1-4) and beta (1-6)-linked disaccharides. On the other hand, with beta-galactosidase from Streptococcus 6646K, beta (1-3)-linked disaccharide was predominant together with beta (1-4)-linked isomer. Gal beta (1-3)GlcNAc (4), Gal beta (1-4)GlcNAc (5) and Gal beta (1-6)GlcNAc (6) were also synthesized with beta-galactosidase from S. 6646K and B. bifidum with 2-acetamido-2-deoxy-glucopyranose as the acceptor and PNPGal as the donor. In both cases, the beta (1-4)-linked disaccharide was predominantly produced. In addition, a comparative study was carried out to determine the regioselectivity of the transglycosylation reaction as well as the hydrolytic specificity toward the same linked disaccharides.
在磷酸三乙酯缓冲溶液（20 - 60%）中，使用来自四种不同来源的β-半乳糖苷酶催化将β-D-吡喃半乳糖基从4-硝基苯基-β-D-吡喃半乳糖苷转移至2-乙酰氨基-2-脱氧-吡喃半乳糖的羟基上，以合成Galβ(1-3)GalNAc（1）、Galβ(1-4)GalNAc（2）和Galβ(1-6)GalNAc（3）。当使用来自多色青霉和米曲霉的β-半乳糖苷酶作为催化剂时，β(1-6)连接的二糖是主要产物。然而，使用来自两歧双歧杆菌的β-半乳糖苷酶时，主要产物是β(1-4)和β(1-6)连接的二糖。另一方面，使用来自链球菌6646K的β-半乳糖苷酶时，β(1-3)连接的二糖与β(1-4)连接的异构体一起占主导地位。还使用来自6646K链球菌和两歧双歧杆菌的β-半乳糖苷酶，以2-乙酰氨基-2-脱氧-吡喃葡萄糖为受体、PNPGal为供体合成了Galβ(1-3)GlcNAc（4）、Galβ(1-4)GlcNAc（5）和Galβ(1-6)GlcNAc（6）。在这两种情况下，主要生成β(1-4)连接的二糖。此外，还进行了一项比较研究，以确定转糖基化反应的区域选择性以及对相同连接二糖的水解特异性。
