聚乙烯亚胺诱导的仿生硅化提高固定化酶的稳定性  

Improvement in the Stability of Immobilized Enzyme by Polyethylenimine-Induced Biomimetic Silicification

作　　者：白姝[1] 朱云风 孙彦[1] 余林玲 Bai Shu;Zhu Yunfeng;Sun Yan;Yu Linling(School of Chemical Engineering and Technology,Tianjin University,Tianjin 300350,China)

机构地区：[1]天津大学化工学院,天津300350

出　　处：《天津大学学报（自然科学与工程技术版）》2021年第1期10-18,共9页Journal of Tianjin University：Science and Technology

基　　金：国家自然科学基金资助项目(21878223)。

摘　　要：设计具有高稳定性、活性、选择性的酶-载体复合物一直是固定化酶领域的研究重点.本文构建了聚乙烯亚胺(PEI)修饰的磁性纳米粒子(MNPs),并用此作为载体(MNPs-PEI)通过静电作用吸附固定磷酸烯醇式丙酮酸羧化酶(PEPcase),最后在该复合物(MNPs-ENZ)表面利用PEI诱导的仿生硅化作用生长二氧化硅壳层(MNPsENZ@SiO_2),以提高固定化酶的稳定性.利用透射电子显微镜、X射线光电子能谱、振动样品磁强计、纳米粒度分析仪等表征方式证明了载体的成功合成、酶的顺利负载以及二氧化硅的成功包覆.结果表明,经仿生硅化后的固定化酶显著地提高了酶的稳定性,使得PEPcase在极端温度(50℃)或极端pH值(pH=10.0)条件下孵育1 h后依旧保持93%的活性,并且在8个循环后保存77%的酶活力.这说明仿生硅化的方法能够提高固定化酶的稳定性,该方法简便快速,环境友好,为固定化酶的进一步应用提供了参考.Designing enzyme-carrier complexes with high stability,activity,and selectivity has long been the focus of the field of enzyme immobilization.In this work,we prepared polyethyleneimine(PEI)-modified magnetic nanoparticles(MNPs)for the immobilization of phosphoenolpyruvate carboxylase(PEPcase)by electrostatic interaction,which is denoted as MNPs-ENZ.Then,to improve the stability of the immobilized enzyme,we coated the surface of the MNPs-ENZ with a silica layer by PEI-induced biomimetic silicification,which is denoted as [e-mail] PEI-modified nanoparticles(MNPs-PEI)and two immobilized enzymes(MNPs-ENZ and MNPs-ENZ@SiO2)were characterized by transmission electron microscopy,X-ray photoelectron spectroscopy,a vibrating sample magnetometer,and a nanometer-particle-size analyzer.The results reveal that the modification of PEI,immobilization of PEPcase,and coating of the silica layer were successful and that biomimetic silicification greatly improves the thermal stability,pH stability,and recyclability of [e-mail] an example,93%of the activity was maintained after incubation for 1 h even at 50℃or pH=10.0,and 77%of activity was maintained after eight cycles.The above results indicate that MNPs-PEI can improve the stability of PEPcase and is a suitable carrier for enzyme immobilization.In addition,biomimetic silicification could further enhance the stability and dispersion of the immobilized enzyme,thereby confirming its potential for commercial application.

关 键 词：磁性纳米颗粒 聚乙烯亚胺 仿生硅化 磷酸烯醇式丙酮酸羧化酶 固定化酶 

分 类 号：Q814[生物学—生物工程]