低pKa属性苯硼酸基亲和载体的构建及其在醛糖-酮糖异构化体系中的应用基础研究

低pKa属性苯硼酸基亲和载体在碳水化合物分离纯化和生物催化领域有着广阔的应用潜力。本项目拟构建具有低pKa属性的苯硼酸基亲和载体，建立载体结构特性与糖分子特异性识别之间的构-效关系，继而为具有“目的属性”的智能型苯硼酸基亲和载体的设计和构建提供理论依据。结合课题组近期在实验中所发现的苯硼酸基亲和载体对部分酮糖的亲和吸附效应明显高于其对应的醛糖这一现象，拟将构建的苯硼酸基亲和载体应用于醛糖-酮糖的分离纯化，明晰载体对酮糖的特异性亲和吸附机制，考察其应用于醛糖-酮糖体系分离纯化的普适性。在此基础上，进一步探究苯硼酸基亲和载体定向辅助醛糖-酮糖异构化及同步分离纯化目标酮糖的效能。结合原位表征技术、量子化学计算以及分子生物学软件等，明确其辅助催化途径及定向调控机制。本研究创新性地将低pKa属性苯硼酸基亲和载体应用于分离纯化和辅助催化，为酮糖的高效分离和醛糖-酮糖异构化反应的定向调控提供了新的途径。

Boronate-affinity materials have recently gained rapid development and found increasing applications in carbohydrates isolation and bio-production. In the current project, boronate affinity adsorbent with low pKa has been wisely constructed. The structure-function relationships of the prepared boronate affinity adsorbent and its sugar recognition performance have been established, which could furtherly provide guidance for the rational construction of the multi-purpose boronate affinity materials. Interesting, preliminary studies in our group reveal that the boronate affinity materials generally exhibit a relatively higher binding affinity towards typical ketoses than their corresponding aldoses, especially for those fructofuranose-containing ketoses. Thus, an efficient and innovative strategy by using the prepared boronate affinity adsorbent was wisely developed for the highly efficient separation and purification of ketose from aldose-ketose mixtures, and the selective and reversible adsorption affinity mechanism was indeed investigated. On this basis, the efficiency of the prepared boronate affinity adsorbent in the directionally assisted aldose-to-ketose isomerization (chemical/enzymatic) and simultaneous isolation of target ketoses was furtherly investigated. In situ characterization, quantum chemistry calculation and molecular biology analysis were carried out to help explore the catalytic pathway and identified the mechanism of the directional control. This trial validates the use of boronate affinity adsorbent with low pKa for an effective simultaneous directional production and isolation of high-purity ketoses from the isomerization of aldoses.