Rodionova N A, Gorbacheva I V, Buĭvid V A
Biokhimiia. 1977 Apr;42(4):659-71.
Two endo-1,4-beta-zylanases (m. w. 24,000 and 41,000) and six exo-1,4-beta-xylosidases, differing in their molecular weights and isoelectric points, were found in a xylanase preparation from Aspergillus niger, using different methods of fractionation. An electrophoretically homogeneous exo-1,4-beta-xylosidase (m. w. 30,000) purified 120-fold, with pI 4.6, having optimal effect on methyl-beta-D-xyloside at pH 3.0 was obtained. Exo-1,4-beta-xylosidase splits off xylose from the ends of the xylan chains at xylotriose, xylobiose and methyl-beta-D-xyloside and is characterized by a high transglycosilase activity. An electrophoretically homogeneous endo-1,4-beta-xylanase (m. w. 24,000) purified 250-fold, with pI 4.2 and optimal effect on carboxymethylxylan at pH 4.2 was isolated. Endo-1,4-beta-xylanase splits arabinoglucuronoxylan to form xylooligosaccharides; however, it does not hydrolyze xylobiose.
利用不同的分级分离方法，在黑曲霉的木聚糖酶制剂中发现了两种内切-1,4-β-木聚糖酶（分子量分别为24,000和41,000）以及六种外切-1,4-β-木糖苷酶，它们的分子量和等电点各不相同。获得了一种经电泳均一的外切-1,4-β-木糖苷酶（分子量30,000），纯化了120倍，其等电点为4.6，在pH 3.0时对甲基-β-D-木糖苷具有最佳作用。外切-1,4-β-木糖苷酶从木聚糖链的末端切下木糖，作用于木三糖、木二糖和甲基-β-D-木糖苷，其特点是具有高转糖基酶活性。分离出一种经电泳均一的内切-1,4-β-木聚糖酶（分子量24,000），纯化了250倍，其等电点为4.2，在pH 4.2时对羧甲基木聚糖具有最佳作用。内切-1,4-β-木聚糖酶将阿拉伯糖葡糖醛酸木聚糖分解形成木寡糖；然而，它不能水解木二糖。
