表面偶极离子亲水磁珠固定化异柠檬酸裂解酶及其表征  

Immobilization of Isocitrate Lyase on Amphoteric Ion-Rich Hydrophilic Magnetic Beads and Its Characterization

作　　者：段昌园 姜雪 曾宏威 杨晓兰[1] DUAN Changyuan;JIANG Xue;ZENG Hongwei;YANG Xiaolan(College of Laboratory Medicine,Chongqing Medical University,Chongqing 400016,China)

机构地区：[1]重庆医科大学检验医学院,重庆400016

出　　处：《食品与生物技术学报》2024年第1期20-28,共9页Journal of Food Science and Biotechnology

基　　金：国家自然科学基金面上项目(82273900);重庆市自然科学基金面上项目(CSTC2019jcyj-msxmX0166)。

摘　　要：比较两种亲水磁珠固定化结核分枝杆菌异柠檬酸裂解酶(Mycobacterium tuberculosis isocitrate lyase,Mt ICL)并优化,为天然产物中Mt ICL先导抑制剂的亲和富集筛选提供适用的固定化酶。构建6×His-pET28a-ICL,经E.coli BL21(DE3)重组表达、Ni^(2+)-NTA柱纯化和酶学性质表征获得Mt ICL(重组蛋白质)。用羧基功能化和Ni^(2+)-NTA功能化制备两种表面偶极离子亲水磁珠固定化Mt ICL,比较其固载量、酶活力、稳定性及对已知抑制剂的响应。羧基磁珠固定化酶表观保留比活显著高于Ni^(2+)-NTA固定化酶。当羧基磁珠与重组蛋白质加样质量比为60∶1时,固定化酶表观保留比活可达游离酶的85%,此时羧基磁珠对Mt ICL表观固载量为(7.2±0.2)mg/g(以磁珠质量计,n=3)。羧基磁珠固定化Mt ICL对衣康酸的亲和力与游离酶无显著差异(P>0.05),且稳定性更强。此羧基磁珠固定化Mt ICL可望作为磁分离、亲和富集筛选天然产物中Mt ICL抑制剂类抗结核先导化合物。To provide magnetic immobilized Mycobacterium tuberculosis isocitrate lyase(MtICL)suitable for affinity-driven enrichment screening of MtICL lead inhibitors from natural products,two hydrophilic magnetic beads were compared for immobilization of MtICL under the optimized conditions.MtICL was obtained via expression of recombinant 6×His-pET28a-ICL plasmid in E.coli BL21(DE3)and purification with Ni^(2+)-NTA agarose column followed by characterization of enzymatic properties.Two amphoteric ion-rich hydrophilic magnetic beads,functionalized with carboxyl and Ni^(2+)-NTA,were used to immobilize MtICL,respectively,for comparing their immobilization quantity,enzymatic activity,stability,and affinities for the known inhibitors.The apparent retention specific activity of carboxyl magnetic beads-immobilized MtICL was significantly higher than that of Ni^(2+)-NTA magnetic bead-immobilized MtICL.When the mass ratio of carboxyl magnetic beads to protein was optimized to 60∶1,the apparent retention activity of the immobilized enzyme reached 85%of that of the free enzyme.The apparent saturated immobilization capacity of carboxyl magnetic beads for MtICL was(7.2±0.2)mg/g(calculated by magnetic beads weight,n=3).There was no significant difference in the affinity of carboxyl magnetic bead-immobilized MtICL for itaconic acid compared to that of free MtICL(P>0.05),and the stability was stronger.MtICL immobilized on carboxylic magnetic beads is suitable for the magnetic separation,affinite-driven,enrichment,and screening of MtICL inhibitors as anti-tuberculosis lead ligands from natural products.

关 键 词：结核病 异柠檬酸裂解酶 亲水磁珠 酶固定化 

分 类 号：Q814[生物学—生物工程]