Synthesis of chitin and chitosan stereoisomers by thermostable α-glucan phosphorylase-catalyzed enzymatic polymerization of α-D-glucosamine 1-phosphate
Synthesis of chitin and chitosan stereoisomers by thermostable α-glucan phosphorylase-catalyzed enzymatic polymerization of α-D-glucosamine 1-phosphate
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DOI：
10.1039/c5ob00167f
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发表时间：
2015-01-01
影响因子：
3.2
通讯作者：
Yamamoto, Kazuya
中科院分区：
文献类型：
--
作者：
Kadokawa, Jun-ichi;Shimohigoshi, Riko;Yamamoto, Kazuya
两种氨基多糖立体异构体，即α-(1 -> 4)-和β-(1 -> 4)-连接的(N-乙酰基)-D-葡萄糖胺聚合物之间的关系在多糖科学领域中具有重要意义，因为它们对应于代表性丰富的天然多糖的氨基类似物，即。直链淀粉和纤维素。虽然后者的葡糖胺聚合物是众所周知的天然多糖、甲壳素和壳聚糖（由β-(1 -> 4)-连接的N-乙酰基-D-葡糖胺和D-葡糖胺组成的线性多糖）的基础，但据我们所知，前者（α-(1 -> 4)-连接的）在自然界中尚未观察到。出于这些研究的目的，此类非天然氨基多糖的合成是通过热稳定性α-葡聚糖磷酸化酶（来自 Aquifex aeolicus VF5）催化的 α-D-葡糖胺 1-磷酸 (GlcN-1-P) 的酶聚合，在含有 Mg2+ 离子的氨缓冲液中通过连续的 α-葡糖胺酰化，从而产生 α-(1 -> 4)-连接的D-葡萄糖胺聚合物，对应于壳聚糖立体异构体的结构。随后产物的 N-乙酰化得到氨基多糖，对应于甲壳素立体异构体。
The relationship between two aminopolysaccharide stereoisomers, namely alpha-(1 -> 4)- and beta-(1 -> 4)-linked (N-acetyl)-D-glucosamine polymers, is of significant interest within the field of polysaccharide science, as they correspond to amino analogs of the representative abundant natural polysaccharides, viz. amylose and cellulose. While the latter glucosamine polymer is the basis of well-known natural polysaccharides, chitin and chitosan (linear polysaccharides composed of beta-(1 -> 4)-linked N-acetyl-D-glucosamine and D-glucosamine), to the best of our knowledge, the former (alpha-(1 -> 4)-linked) has not been observed in nature. For the purpose of these studies, the synthesis of such non-natural aminopolysaccharides was performed by the thermostable a-glucan phosphorylase (from Aquifex aeolicus VF5)-catalyzed enzymatic polymerization of alpha-D-glucosamine 1-phosphate (GlcN-1-P), via successive alpha-glucosaminylations, in ammonia buffer containing Mg2+ ions, resulting in the production of the alpha-(1 -> 4)-linked D-glucosamine polymers, corresponding to the structure of the chitosan stereoisomer. Subsequent N-acetylation of the products gave the aminopolysaccharides, corresponding to the chitin stereoisomer.