Nerinckx Wim, Broberg Anders, Duus Jens Ø, Ntarima Patricia, Parolis Lesley A S, Parolis Haralambos, Claeyssens Marc
Department of Biochemistry, Physiology and Microbiology, Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium.
Carbohydr Res. 2004 Apr 28;339(6):1047-60. doi: 10.1016/j.carres.2004.02.017.
The structures of several enzymatic hydrolysis products of Nothogenia erinacea seaweed xylan, a linear homopolymer with mixed beta-(1-->3)/beta-(1-->4) linkages, were analysed by physicochemical and biochemical techniques. With the glycoside hydrolase family 10 beta-(1-->4)-xylanase from Cryptococcus adeliae, hydrolysis proceeds to a final mixture of products containing a mixed linkage-type triose as a major compound, whereas with the family 11 xylanase from Thermomyces lanuginosus this is a mixed linkage tetraose. The Cryptococcus xylanase is shown to be capable of also catalysing the hydrolysis of beta-(1-->3) linkages, that is this of a mixed type tetraose intermediary formed, in accordance with the broader substrate specificity of family 10 enzymes. From a partial degradation experiment with the T. lanuginosus xylanase, a series of higher mixed oligosaccharides were isolated and identified. The observed oligosaccharide intermediates and splicing pattern indicate an irregular beta-(1-->3)/beta-(1-->4) linkage distribution within the linear d-xylose polymer. Similar results were obtained with rhodymenan, the seaweed xylan from Palmares palmata.
对具有β-(1→3)/β-(1→4)混合连接的线性均聚物——海刺参（Nothogenia erinacea）海藻木聚糖的几种酶促水解产物的结构，采用物理化学和生化技术进行了分析。使用来自阿氏隐球菌（Cryptococcus adeliae）的糖苷水解酶家族10的β-(1→4)-木聚糖酶，水解生成的最终产物混合物中，主要化合物是一种混合连接型三糖；而使用来自嗜热栖热菌（Thermomyces lanuginosus）的家族11木聚糖酶时，主要产物是一种混合连接四糖。已证明阿氏隐球菌木聚糖酶也能够催化β-(1→3)连接的水解，即根据家族10酶更广泛的底物特异性，催化形成一种混合类型的四糖中间体。通过用嗜热栖热菌木聚糖酶进行的部分降解实验，分离并鉴定了一系列更高的混合寡糖。观察到的寡糖中间体和拼接模式表明，线性d-木糖聚合物内β-(1→3)/β-(1→4)连接分布不规则。从掌状红皮藻（Palmares palmata）的海藻木聚糖——红藻多糖（rhodymenan）中也获得了类似结果。
