The challenge for polymeric enzyme reactors at present is to selectively control the enzymolysis rate in complex conditions. Additionally, the fabrication methodology is hindered by complex processes, especially for achieving diverse stimuli responsiveness and functions. Here, we reported a kind of pH-sensitive polymer, poly(styrene-co-maleic anhydride-acrylic acid) (PS-MAn-AA)-based hybrid enzyme reactor. It comprised magnetic nanoparticles and a pH-sensitive PS-MAn-AA porous polymer membrane made by breath figure method. The enzyme l-asparaginase (l-ASNase) could covalently bond on the surface of the pH-sensitive porous polymer membrane (pH-PPM), and the resultant enzyme reactor was characterized by Fourier transform infrared spectroscopy and vibrating sample magnetometer. The apparent Michaelis–Menten constants (Km and Vmax) of the l-ASNase enzyme reactor at different pH values were determined by a chiral ligand-exchange capillary electrophoresis method with l-asparagine as the substrate. The Vmax value of the l-ASNase enzyme reactor (0.67 mM/min) was almost 3-fold of that of the free l-ASNase (0.23 mM/min) at pH 8.2. Its ability to precisely control the enzymolysis rate in complex conditions is triggered primarily by the pH of the buffer solution, allowing controlled enzymatic reactions and displaying excellent stability and reusability of the proposed pH-PPM. This strategy for porous polymer membrane enzyme reactor fabrication has established a platform for enzyme efficiency adjusting. These valve-like distinguished features highlight the outstanding potential of stimuli-responsive enzyme reactor applied for enzyme immobilization and enzyme-related disease treatment.
Xiaonan Wang,Meiwen Wang,Yuanyuan Zhang,Xiaocao Miao,Yuanyuan Huang,Juan Zhang,Lizhou Sun
A new strategy to fabricate electrochemical biosensor is reported based on the linkage of enzyme substrate , thereby an electrochemical method to detect aldolase activity is established using pectin-thionine complex (PTC) as recognization element and signal probe . The linkage effect of fructose-1,6-bisphosphate (FBP), the substrate of aldolase, can be achieved via its strong binding to magnetic nanoparticles (MNPs)/aminophenylboronic acid (APBA) and the formation of phosphoramidate bond derived from its reaction with p -phenylenediamine (PDA) on the surface of electrode. Aldolase can reversibly catalyze the substrates into the products which have no binding capacity with MNPs/APBA, resulting in the exposure of the corresponding binding sites and its subsequent recognization on signal probe. Meanwhile, signal amplification can be accomplished by using the firstly prepared PTC which can bind with MNPs/APBA, and accuracy can be strengthened through magnetic separation. With good precision and accuracy, the established sensor may be extended to other proteins with reversible catalyzed ability.
危险品化学品经营许可证（带存储）