Synthesis of a cellobiosylated dimer and trimer and of cellobiose-coated polyamidoamine (PAMAM) dendrimers to study accessibility of an enzyme, cellodextrin phosphorylase
Synthesis of a cellobiosylated dimer and trimer and of cellobiose-coated polyamidoamine (PAMAM) dendrimers to study accessibility of an enzyme, cellodextrin phosphorylase
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DOI：
10.1002/ejoc.200300018
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发表时间：
2003-07-01
影响因子：
2.8
通讯作者：
Hayashi, K
中科院分区：
文献类型：
--
作者：
Choudhury, AK;Kitaoka, M;Hayashi, K
为了研究纤维素糊精磷酸化酶（CDP）对多价簇状碳水化合物的可及性，首次合成了纤维素生物基化的二聚体10和三聚体12，以及在PAMAM树状大分子外表面分别含有4、8、16、32和64个纤维素二糖单元的纤维素二糖包被PAMAM树状大分子14、16、18、20和22，并将其作为CDP酶的受体底物。研究发现，CDP能够将葡萄糖基片段从葡萄糖-1-磷酸（Glc-1-P）转移到这些合成的簇状纤维素生物基化糖缀合物和纤维素二糖包被的PAMAM树状大分子中，从而成为CDP的受体底物。研究发现，CDP与较小的纤维素生物基化糖偶联物和含有多达8个纤维素二糖单位的PAMAM树状大分子相互作用的能力与纤维素二糖相似。然而，当PAMAM树状大分子含有16个纤维素二糖单元时，CDP的这种能力有所降低，而当PAMAM树状大分子含有32个和64个纤维素二糖单元时，CDP的这种能力显著降低。这可能是由于它们的立体体积，CDP酶不再能够将它们正确地固定在活性位点上。(C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)。
To examine the accessibility of the enzyme cellodextrin phosphorylase (CDP) towards multivalent cluster carbohydrates, the cellobiosylated dimer 10 and trimer 12, as well as the cellobiose-coated PAMAM dendrimers 14, 16, 18, 20 and 22, with four, eight, sixteen, thirty-two and sixty-four cellobiose units at the outer surface of PAMAM dendrimers, respectively, have been synthesized for the first time and used as acceptor substrates for the enzyme CDP. It was found that CDP was able to transfer a glucosyl moiety from glucose-1-phosphate (Glc-1-P) into these synthesized cluster cellobiosylated glycoconjugates and cellobiose-coated PAMAM dendrimers, which were thus acceptor substrates for CDP. It was found that the ability of CDP to interact with smaller cellobiosylated glyconjugates and with PAMAM dendrimers containing up to eight cellobiose units was similar to that seen with cellobiose. However, this capability of CDP was somewhat lessened with the PAMAM dendrimer containing sixteen cellobiose moieties and dramatically decreased towards PAMAM dendrimers with thirty-two and sixty-four cellobiose units. This might be due to their steric bulk, CDP enzyme no longer being able to hold them properly on its active site. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).