Chen Yanjun, Dou Wenfang, Li Heng, Shi Jinsong, Xu Zhenghong
Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Pharmaceutical Science, Jiangnan University, Wuxi, 214122, PR China.
Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Pharmaceutical Science, Jiangnan University, Wuxi, 214122, PR China.
Carbohydr Res. 2018 Dec;470:36-41. doi: 10.1016/j.carres.2018.06.005. Epub 2018 Jul 12.
Alginate oligosaccharides are depolymerization products of alginate by enzymatic degradation or physicochemical treatments. Alginate lyase has received great interests due to its use in oligosaccharide preparation. The substrate specificity of alginate lyase directly determines the type and degree of polymerization of alginate oligosaccharides. In this paper, the degradation products of Alginate lyase from Isoptericola halotolerans CGMCC 5336 were size-fractionated by gel filtration chromatography and the fractions were characterized by TLC, HPLC, MS and H NMR spectroscopy. The Mw values for these fractions were 352, 528, 704 Da which represented di-, tri-, and tetrasaccharide fragments, respectively. The H NMR revealed that the non-reducing ends of these oligosaccharides were 4-deoxy-L-erythro-hex-4-enepyranosyluronate and the reducing ends of these oligosaccharides were all guluronic acid. Therefore, it is believed that the alginate lyase produced by Isoptericola halotolerans CGMCC 5336 was capable of performing β elimination on guluronic acid residue so that low molecular weight oligosaccharides with guluronic acid on the reducing end could be obtained in this way.
海藻酸寡糖是海藻酸通过酶降解或物理化学处理得到的解聚产物。由于其在寡糖制备中的应用，海藻酸裂合酶受到了广泛关注。海藻酸裂合酶的底物特异性直接决定了海藻酸寡糖的类型和聚合度。本文采用凝胶过滤色谱法对嗜盐栖白蚁Isoptericola halotolerans CGMCC 5336产生的海藻酸裂合酶的降解产物进行了分级分离，并用薄层色谱法（TLC）、高效液相色谱法（HPLC）、质谱法（MS）和核磁共振氢谱法（H NMR）对各组分进行了表征。这些组分的分子量分别为352、528、704 Da，分别代表二糖、三糖和四糖片段。核磁共振氢谱显示，这些寡糖的非还原端为4-脱氧-L-赤藓糖-己-4-烯吡喃糖醛酸，还原端均为古洛糖醛酸。因此，可以认为嗜盐栖白蚁Isoptericola halotolerans CGMCC 5336产生的海藻酸裂合酶能够对古洛糖醛酸残基进行β消除反应，从而得到还原端带有古洛糖醛酸的低分子量寡糖。
