Hu Jie, Li Songjun, Liu Bailing
School of Materials Science and Engineering, Jiangsu University, Xue Fu Road 301, Zhenjiang 212013, China.
Biotechnol J. 2006 Jan;1(1):75-9. doi: 10.1002/biot.200500022.
In this work we use micro-size poly(methyl methacrylate)/acrylaldehyde microspheres as a support for pepsin immobilization. The aldehyde groups on the microspheres offer a very simple, mild and firm combination for enzyme immobilization. The amount of enzyme we can bind to this support reaches 82 mg/g, which is much higher than for other supports (mostly less than 10 mg/g). Compared to free enzyme, the Km of immobilized enzyme is increased, whereas the Vmax is decreased. Further, the Vmax/Km value for immobilized pepsin is about 50% of the value for free enzyme. This is better than values reported previously, generally lower than 35%. The optimum temperature shifts from 43 degrees C for free pepsin to 47 degrees C. However, the optimum pH does not change between free and immobilized enzyme. This improved resistance of the immobilized enzyme towards changes in temperature and pH also shows that the aldehyde modified poly(methyl methacrylate)/acrylaldehyde microspheres can be a valuable support for pepsin immobilization.
在本研究中，我们使用微米级聚甲基丙烯酸甲酯/丙烯醛微球作为固定化胃蛋白酶的载体。微球上的醛基为酶的固定提供了一种非常简单、温和且牢固的结合方式。我们能够结合到该载体上的酶量达到82 mg/g，这比其他载体（大多低于10 mg/g）要高得多。与游离酶相比，固定化酶的米氏常数（Km）增加，而最大反应速度（Vmax）降低。此外，固定化胃蛋白酶的Vmax/Km值约为游离酶该值的50%。这比之前报道的值要好，之前的值通常低于35%。最适温度从游离胃蛋白酶的43℃转变为47℃。然而，游离酶和固定化酶的最适pH没有变化。固定化酶对温度和pH变化的这种抗性增强也表明，醛基修饰的聚甲基丙烯酸甲酯/丙烯醛微球可以成为固定化胃蛋白酶的一种有价值的载体。
