Supramolecular Control in Synthetic Enzyme-Mimetic Materials

酶是生物过程中的催化剂，可以加速生物反应。它们在温和的条件下具有非凡的催化效率，在众多化合物的混合物中往往具有显著的选择性。这些特征是非常可取的，但在非生物系统中很难实现。爱荷华州立大学赵燕教授的研究小组开发了新的方法来制备在尺寸、水溶性以及更重要的催化行为方面模仿酶的合成系统。这项研究有望极大地提高合成催化剂用于化学工业和生物质转化的重要反应的能力。它将学生研究人员培养成专业科学家，使他们接触到物理有机化学、超分子化学、催化和聚合物化学方面的广泛技能。酶经常进行化学反应，从纯合成的角度来看，效率和选择性很难实现。尽管分子识别是酶催化剂的基本特征，但化学家构建底物特定活性中心的能力有限。该项目由化学系大分子、超分子和纳米化学计划资助，支持爱荷华州立大学赵燕教授研究通过在交联型表面活性剂胶束内分子印迹来构建用于酯和缩醛水解酶的新方法。这些催化剂有望具有酶的关键特征，例如通过非共价力选择性地结合底物，在活性中心内正确定位合适的官能团以获得最佳反应活性，以及底物优先于产物结合。通过系统地调节活性中心的大小和形状以及活性中心中催化基团的类型和位置来最大化催化效率和选择性。

Enzymes are catalysts involved in biological processes to speed up biological reactions. They have extraordinary catalytic efficiency under mild conditions and tend to be remarkably selective in a mixture of numerous compounds. These features are highly desirable but have been difficult to achieve in non-biological systems. The research group of Professor Yan Zhao at Iowa State University develops novel approaches to prepare synthetic systems that mimic enzymes in their dimension, water-solubility, and, more importantly, catalytic behavior. The research is expected to greatly enhance the capabilities of synthetic catalysts for reactions important to chemical industry and biomass conversion. It trains student researchers into professional scientists by exposing them to a wide range of skills in physical organic chemistry, supramolecular chemistry, catalysis, and polymer chemistry. Enzymes frequently perform chemical reactions with efficiency and selectivity difficult from a pure synthetic perspective. Although molecular recognition is an essential feature of enzymatic catalysts, chemists have limited abilities to construct substrate-specific active sites. This project, funded by the Macromolecular, Supramolecular and Nanochemistry Program of the Chemistry Division, supports Professor Yan Zhao of Iowa State University to study novel methods to construct artificial enzymes for the hydrolysis of esters and acetals, through molecular imprinting within cross-linked surfactant micelles. These catalysts are anticipated to have key features of enzymes such as selective binding of the substrate via non-covalent forces, correct positioning of appropriate functional groups within the active site for optimal reactivity, and preferential binding of the substrate over the product. Catalytic efficiency and selectivity is maximized through systematic tuning of the size and shape of the active sites, as well as the type and the position of the catalytic groups in the active sites.