自组装磁性聚苯乙烯微球固定化木瓜蛋白酶

Immobilization of Papain by Layer-by-Layer Self-Assembly on Magnetic Polystyrene Microspheres

通过逐层自组装（Layer—By—Layerself-assembly）的方式在自制的经过磺化的聚苯乙烯微球上连接聚电解质和磁性物质制备了核壳结构的磁性微球，并用此磁性微球固定木瓜蛋白酶。固定酶在温度30℃，m（酶）：m（球）=37．98：100，pH=6．0，固定化时间1．0h的条件下，固定化率可达93．0％。固定化酶的最佳使用温度为50℃，最佳使用pH=8．0，使用3次或80℃保存90～120min活性约降一半。

Magnetic polystyrene（PS） microspheres were prepared by layer-by-layer self-assembly technique. The core-shell microspheres were constructed by alternately depositing negative and positive polyeleetrolytes onto sulfate-stabilized PS latex particles. And then, papain was immobilized on them. The best circumstance of enzyme immobilization was determined ： pH = 6.0, 1.0 h, 30 ℃, mass ratio （ papain ： microspheres ） 37.98%. And the largest ratio of enzyme immobilization could reach 93.0%. The properties of the immobilized enzyme were also studied. The best application temperature and pH were 50 ℃ and 8.0, respectively.When used for 3 times or reserved for 1.5 - 2.0 h at 80 ℃, the activity of the immobilized papain would fall by nearly half.