磁性聚乙烯醇微球固定化α-淀粉酶的研究

磁性聚乙烯醇微球为载体,采用戊二醛交联法固定化α-淀粉酶,并对固定化酶的理化性质等进行了研究。结果表明,磁性固定化α-淀粉酶的总活力、蛋白载量、比活、活性回收率分别为1107.89U/g微球、125.36mg/g微球、8.84U/mg蛋白质和37.96%;固定化α-淀粉酶的反应最适温度和最适pH分别为110℃和7.0;固定化α-淀粉酶对金属离子Mg2+、Fe2+、Zn2+和Cu2+的抑制作用的忍耐性比自由酶的明显提高;α-淀粉酶被固定化后其热稳定性、操作稳定性、pH稳定性均比自由酶的明显提高。固定化α-淀粉酶在4℃,pH7.0的缓冲液中保存30d,其活力仍保持最初活力的91.6%,这比其自由酶的高12.3%。

α-amylase was immobilized by crosslinking with glutaraldehyde onto magnetic polyvinylalcohol microsphere and the physical and chemical properties of the magnetic immobilized enzyme were studied. The result shown that the total activity, protein binding, specific activity and activity retention of the immobilized α-amylase were 1107.89U/g, 125.36mg/g, 8.84U/mg and 37.96%, respectively. The enzyme optimum temperature was 110℃ and optimum pH was 7.0. ions including Mg^2＋, Fe^2＋, Zn^2＋ and Cu^2＋ inhabited the enzyme. However, the effect of these ions on immobilized β- amylase was obviously less than on its free state. As compared with the free-state α-amylase, the operational, thermal and pH stability of the immobilized enzyme were improved significantly. After being stored at 4℃, pH 7.0 for 30 days, the immobilized a-amylase retained 91.6% of its initial activity which was 12.3% more than that of free enzyme.