不同介孔材料固定青霉素酰化酶的稳定性研究

介孔材料由于具有在2～30nm之间可调的纳米级规则孔道、大比表面积和强吸附性能而成为固定化酶的优良载体．将酶固定于介孔材料的孔道中制备成的固定化酶与溶液酶相比，有易于与产物分离，并可回收和反复使用，可降低生产成本，减少酶的自水解和保持酶的活性．青霉素酰化酶（Penicillin acylase，PGA，EC．3．5．1．11）又称为青霉素酰胺酶或青霉素氨基水解酶，该酶属于球蛋白，分子量较大，由2个亚基组成：分子量为19500的含有侧链结合位点的亚基和分子量为60000的含有催化位点的亚基．

Stability of Penicillin G Acylase Immobilized on Different Silica Mesoporous Materials

Silica mesoporous materials were synthesized and used as the supporting materials for immobilization of enzyme.Penicillin G acylase,an enzyme which was used to produce 6-APA in pharmaceutical industry,was immobilized in the mesoporous materials by the immersion method.The stabilities of the immobilized penicillin G acylase were studied.After incubation at 60 ℃ for 2 h,the activity of immobilized penicillin G acylase remained 80% in the best case.At higher or lower pH,the free enzyme was deactivated quickly,while the immobilized enzyme still retained active.The result of operational stability showed that the immobilized(enzyme) retained 70% of its initial activity after operating for 6 times.These results showed that the stabilities of immobilized penicillin G acylase,related to the pore size of mesoporous materials,were increased significantly compared with those of free enzyme.The improvement of stabilities of immobilized enzyme was significant when the pore size of the mesoporous materials matched the enzyme molecule size.