Hydrophobic pockets built in polymer micelles enhance the reactivity of Cu 2+ ions
Hydrophobic pockets built in polymer micelles enhance the reactivity of Cu 2+ ions
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聚合物胶束中内置的疏水袋增强了 Cu 2 离子的反应性
DOI：
10.1039/d3qm00110e
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发表时间：
2023
影响因子：
7
通讯作者：
He, Jie
中科院分区：
文献类型：
--
作者：
Wei, Zichao;Liu, Chung-Hao;Luo, Qiang;Thanneeru, Srinivas;Angeles-Boza, Alfredo M.;Nieh, Mu-Ping;He, Jie
我们报告的疏水性增强的反应性的铜离子作为酯水解酶。在两亲性聚苯乙烯-聚（N′ N-二甲基丙烯酰胺）嵌段共聚物（PS-b-PDMA）中，采用含吡啶甲基胺（DPA）的可逆加成-断裂链转移剂，通过改变合成顺序（先疏水或先亲水）来控制DPA结合基序在聚合物胶束疏水核或水合冠上的位置. Cu 2+位点的疏水性对酯水解酶的催化效率显示出显著的影响（高达60倍以上的活性）。采用两种不同的动力学模型，包括Michaelis-Menten模型和反饱和动力学模型，定量分析了底物与Cu 2+位点的结合常数Kb，结果表明疏水性有利于底物与较小尺寸聚合物胶束中Cu 2+位点的结合，但Kb随胶束直径呈指数衰减。尽管扩散障碍，疏水性显示出深远的影响，催化速率常数kc的措施结合底物的产品的单一转化率。与具有类似尺寸的胶束相比，完全由Cu 2+位点的疏水微环境赋予的水解酶活性有16-20倍的动力学增强。我们的研究结果表明，含Cu 2+胶束的疏水性如何影响催化效率，并潜在地说明了一种有前途的方式设计的仿生催化剂。
We report the hydrophobicity-enhanced reactivity of Cu2+ ions as an ester hydrolase. Using a dipicolylamine (DPA) containing reversible addition–fragmentation chain transfer agent, the synthetic sequence, either hydrophobic or hydrophilic first in amphiphilic block copolymers of polystyrene-block-poly(N′N-dimethylacrylamide) (PS-b-PDMA), was varied to control the location of the binding motif, DPA, in the hydrophobic core or on the hydrated corona of polymer micelles. The hydrophobicity of Cu2+ sites showed a significant impact (as large as 60 times more activity) on their catalytic efficiency towards ester hydrolase. With two different kinetic modes, including Michaelis–Menten and the reverse saturation kinetics models, the binding constant Kb of the substrates to Cu2+ sites were quantitatively analyzed and we demonstrate that hydrophobicity favors the binding of the substrates to Cu2+ sites at polymer micelles with smaller sizes, however, Kb decays exponentially with micellar diameters. Despite the diffusion barrier, hydrophobicity shows a profound impact on the catalytic rate constant kc that measures the single conversion rate of bound substrates to products. There is a 16–20 times kinetic enhancement in the hydrolase activity, completely endowed by the hydrophobic microenvironment of Cu2+ sites compared to micelles with similar sizes. Our results indicate how the hydrophobicity of Cu2+-containing micelles can impact the catalytic efficiency and potentially illustrate a promising way toward the design of bioinspired catalysts.