Li Rongrong, Jiang Ling, Ye Lidan, Lu Jie, Yu Hongwei
School of Chemical and Material Engineering, Jiangnan University, Wuxi, People's Republic of China.
Biotechnol Appl Biochem. 2014 Sep-Oct;61(5):603-10. doi: 10.1002/bab.1211. Epub 2014 Jun 18.
The esterase BioH from Escherichia coli was covalently immobilized onto the surface of the functional magnetic nanosupport in an oriented manner. The surface of the Fe3O4 nanosupport was modified with acyl azide groups or both acyl azide groups and hydroxyl groups. The protein loading of the support was increased from 55 to 99 mg/g by an improvement in hydrophilicity, and the activity retention of the immobilized esterase on the nanosupport was improved by 40% after hydrophilic modification (30% and 70% of the free BioH, respectively). For the BioH immobilized on the hydrophilic-modified nanosupport, the recovery activity remained 80% of the original activity after 10 times of recycling. The catalytic kinetics and thermo-/pH-stability of the immobilized esterase BioH were also determined and compared with those of the free enzyme. The comparatively high activity retention, improved thermo-/pH-stability, and good reusability of the immobilized enzyme indicate that oriented covalent immobilization is an efficient method for immobilizing esterase BioH.
来自大肠杆菌的酯酶BioH以定向方式共价固定在功能性磁性纳米载体表面。Fe3O4纳米载体表面用酰基叠氮基团或酰基叠氮基团和羟基进行了修饰。通过提高亲水性，载体的蛋白质负载量从55 mg/g提高到99 mg/g，亲水性修饰后，固定在纳米载体上的酯酶的活性保留率提高了40%（分别为游离BioH的30%和70%）。对于固定在亲水性修饰纳米载体上的BioH，经过10次循环后，回收活性仍保持为原始活性的80%。还测定了固定化酯酶BioH的催化动力学和热/ pH稳定性，并与游离酶进行了比较。固定化酶相对较高的活性保留率、改善的热/ pH稳定性和良好的可重复使用性表明，定向共价固定是固定酯酶BioH的有效方法。
