Enzyme-responsive supramolecular nanovalves crafted by mesoporous silica nanoparticles and choline-sulfonatocalix[4]arene [2]pseudorotaxanes for controlled cargo release
Abstract Synthesis and 1 H NMRspectra in D 2 O of 4 betaines and 19 betaine complexes with mineral acids containing 2 or 3 CH 2 groups in the tether, N + –(CH 2 ) n –COO − , n =2,3, and diverse volume of the positively charged groups are reported. In compounds containing three CH 2 groups in the tether and three substituents at the nitrogen atom or α, α′-disubstituted pyridinering, a characteristic
摘要 4 种甜菜碱和 19 种甜菜碱与含有 2 或 3 个 CH 2 基团的无机酸配合物的 D 2 O 合成和 1 H NMR 谱图,N + –(CH 2 ) n –COO - , n =2,3,并且报告了不同体积的带正电基团。在系链中含有三个CH 2 基团和在氮原子或α,α'-二取代吡啶环上含有三个取代基的化合物中,观察到AA'MM'X 2 自旋系统的特征多重峰。这与对反式构象的偏好一致(68-85%)。在系链中具有两个 CH 2 基团或三个 CH 2 基团和未取代吡啶环的化合物的光谱中,多重峰变为三重峰并分别给出表观 A 2 X 2 和 A 2 M 2 X 2 光谱,与没有显着的构象偏好。系链中 CH 2 基团的数量和带电基团的体积都是观察到的 N + CH 2 多样性差异的原因,并反映了构象偏好的变化。根据 PM3 计算,在气相中,类似 gauche 的构象异构体比反式更稳定,但在水溶液中则相反。
Exploiting Neighboring-Group Interactions for the Self-Selection of a Catalytic Unit
作者:Giulio Gasparini、Leonard J. Prins、Paolo Scrimin
DOI:10.1002/anie.200703857
日期:2008.3.14
Enzyme-responsive supramolecular nanovalves crafted by mesoporous silica nanoparticles and choline-sulfonatocalix[4]arene [2]pseudorotaxanes for controlled cargo release
作者:Yu-Long Sun、Yue Zhou、Qing-Lan Li、Ying-Wei Yang
DOI:10.1039/c3cc45216f
日期:——
Mesoporous silica nanoparticles (MSNs) have been surface-functionalized with choline moieties encircled by sulfonatocalix[4]arenes. Two enzyme cleavable sites are incorporated in the stalks for specific enzymes to regulate the release of loaded cargos from MSNs. These gated materials show a clear enzymatic response and proven orthogonality.
Comparison of the substrate selectivity and biochemical properties of human and bacterial γ-butyrobetaine hydroxylase
作者:Anna M. Rydzik、Ivanhoe K. H. Leung、Grazyna T. Kochan、Nikita D. Loik、Luc Henry、Michael A. McDonough、Timothy D. W. Claridge、Christopher J. Schofield
DOI:10.1039/c4ob01167h
日期:——
iron dependent oxygenases have potential for the stereoselective hydroxylation of amino acids and related compounds. The biochemical and kinetic properties of recombinant γ-butyrobetainehydroxylasefrom human and Pseudomonassp. AK1 were compared. The results reveal differences between the two BBOXs, including in their stimulation by ascorbate. Despite their closely related sequences, the two enzymes