碳酸酐酶在功能化Fe3O4-SiO2核壳纳米颗粒上的固定及其性能表征研究

以Fe3O4纳米颗粒为核，正硅酸乙酯（TEOS）为前驱体，通过St?ber法合成了Fe3O4-SiO2核壳纳米颗粒。以γ-缩水甘油醚氧丙基三甲氧基硅烷（GPTMS）为改性剂对纳米颗粒进行改性，得到了环氧基功能化的Fe3O4-SiO2核壳纳米颗粒，随后将碳酸酐酶（carbonic anhydrase，CA）共价固定到纳米颗粒上，以实现CA固定化。采用傅立叶红外（FTIR）、透射电镜（TEM）等手段对载体材料进行表征；以对硝基苯酚乙酸酯（p-NPA）为底物，采用紫外分光光度仪测试酶活力，并对固定化酶进行了性能表征。试验结果表明，固定化酶的热稳定性、贮藏稳定性和循环使用性均优于同等条件下的游离酶，其在循环使用10次后仍保持84.2%的相对酶活力。

Immobilization and characterization of carbonic anhydrase on functionalized Fe3O4-SiO2 core-shell nanoparticles

The Fe3O4-SiO2 core-shell nanoparticles were synthesized by a modified St?ber method using Fe3O4 nanoparticles as the core ethyl orthosilicate(TEOS)as a precursor.Fe3O4-SiO2 core-shell nanoparticles were modified with 3-Glycidyloxypropyl trimethoxysilane to obtain epoxy-functionalized Fe3O4-SiO2 core-shell nanoparticles,and then carbonic anhydrase(CA)was immobilized on the carrier material.The carrier material were characterized by Fourier transform infrared spectroscopy(FTIR)and transmission electron microscope(TEM).By using p-nitrophenol acetate(p-NPA)as a substrate,an ultraviolet spectrophotometer was used to test the enzyme activity,and the performance of immobilized enzyme was characterized.The results show that,the thermal stability,storage stability and recycling performance of the immobilized enzyme are better than the free enzyme under the same conditions,and it still maintains 84.2%relative activity after 10 times of recycling.