van Casteren W H, Dijkema C, Schols H A, Beldman G, Voragen A G
Department of Food Technology and Nutritional Sciences, Wageningen Agricultural University, The Netherlands.
Carbohydr Res. 2000 Feb 25;324(3):170-81. doi: 10.1016/s0008-6215(99)00292-x.
Lactococcus lactis subsp. cremoris B39 grown on whey permeate produced an exopolysaccharide containing L-Rha, D-Gal and D-Glc in a molar ratio of 2:3:2. The polysaccharide was modified using an enzyme preparation from Aspergillus aculeatus, resulting in the release of Gal and a polymer with approximately the same hydrodynamic volume as the native polysaccharide. Linkage analysis and 1H NMR studies of both the native and modified exopolysaccharides elucidated that terminally linked Gal was released during modification and that the chemical structure of the branches within the repeating units is: beta-D-Galp-(1-->4)-beta-D-Glcp-(1-->. 2D NMR experiments (both 1H-1H and 1H-13C) revealed that exopolysaccharide B39 consists of a branched heptasaccharide repeating unit with the following structure: [structure: see text].
在乳清渗透液上生长的乳酸乳球菌亚种cremoris B39产生了一种胞外多糖，其含有摩尔比为2:3:2的L-鼠李糖、D-半乳糖和D-葡萄糖。使用来自棘孢曲霉的酶制剂对该多糖进行修饰，导致半乳糖释放，并产生一种与天然多糖具有大致相同流体力学体积的聚合物。对天然和修饰后的胞外多糖进行的键合分析和1H NMR研究表明，修饰过程中末端连接的半乳糖被释放，并且重复单元内分支的化学结构为：β-D-半乳糖-(1→4)-β-D-葡萄糖-(1→。二维NMR实验（1H-1H和1H-13C）表明，胞外多糖B39由具有以下结构的分支七糖重复单元组成：[结构：见正文]
