Synthesis of highly ordered cellulose II in vitro using cellodextrin phosphorylase
Synthesis of highly ordered cellulose II in vitro using cellodextrin phosphorylase
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DOI：
10.1016/j.carres.2009.10.002
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发表时间：
2009-12-14
影响因子：
3.1
通讯作者：
Samejima, Masahiro
中科院分区：
文献类型：
--
作者：
Hiraishi, Masao;Igarashi, Kiyohiko;Samejima, Masahiro
与天然纤维素材料相比，体外合成纤维素有望提供具有高度均匀结构的定制纤维素材料。在这里，我们报告了纤维糊精磷酸化酶（CDP）从葡萄糖和α-葡萄糖1-磷酸（α G1 P）的酶促合成具有高结晶度的纤维素II。虽然葡萄糖被认为不作为CDP的葡萄糖基受体，但当葡萄糖与α G1 P和CDP混合时，大量的不溶性纤维素沉淀而没有可溶性纤维寡糖的积累。这种现象可以解释为葡萄糖和纤维寡糖之间受体反应性的巨大差异。1H-1 NMR光谱分析表明，这种不溶性纤维素的平均聚合度（DP）为9。TEM观察，连同电子和X-射线衍射研究，表明不溶性纤维素形成的纤维素II，几个μ m的长度和几百nm的宽度，这是大相比，报告的纤维素晶体的片状的单层晶体。层状晶体的厚度为4.5 nm，这相当于DP为9的纤维寡糖的链长，并且与H-1 NMR光谱结果一致。这些结果表明，具有平均DP为9的纤维素低聚糖在体外合成的CDP时，葡萄糖被用作受体，和产品形成高度结晶的纤维素II时，它沉淀。(C)2009爱思唯尔有限公司保留所有权利。
Synthesis of cellulose in vitro is expected to afford tailor-made cellulosic materials with highly homogeneous structure compared to natural cellulosic materials. Here we report the enzymatic synthesis of cellulose II with high crystallinity from glucose and alpha-glucose 1-phosphate (alpha G1P) by cellodextrin phosphorylase (CDP). Although glucose had been believed not to act as a glucosyl acceptor of CDP, a significant amount of insoluble cellulose was precipitated without accumulation of soluble cello oligosaccharides when glucose was mixed with alpha G1P and CDP. This phenomenon can be explained in terms of the large difference in acceptor reactivity between glucose and cello oligosaccharides. H-1 NMR spectrometric analysis revealed that this insoluble cellulose had an average degree of polymerization (DP) of nine. TEM observation, together with electron and X-ray diffraction studies, indicated that the insoluble cellulose formed platelet-shaped single lamellar crystals of cellulose II, several mu m in length and several hundred nm in width; this is large compared to reported cellulose crystals. The thickness of the lamellar crystal is 4.5 nm, which is equivalent to a chain length of a cello oligosaccharide with DP nine and is consistent with the H-1 NMR spectroscopic results. These results suggest that cello oligosaccharides having an average DP of nine are synthesized in vitro by CDP when glucose is used as an acceptor, and the product forms highly crystalline cellulose II when it precipitates. (C) 2009 Elsevier Ltd. All rights reserved.