新型载体PEI/SiO_2固定化青霉素酰化酶的酶学性质  

The Enzymology Property of Penicillin Acylase Immobilized on Novel Composite Support PEI/SIO_2

作　　者：王旭朋[1] 高保娇[1] 张丽萍[1] 

机构地区：[1]中北大学化工与环境学院,山西太原030051

出　　处：《中北大学学报（自然科学版）》2007年第4期335-340,共6页Journal of North University of China(Natural Science Edition)

摘　　要：以PEI/SiO2为复合载体,制备了固定化青霉素酰化酶.考察了游离酶与固定化酶催化反应的最适宜pH值,最适宜温度,固定化酶的连续操作稳定性,以及二者对金属离子的耐受性能及米氏常数.实验结果表明:游离酶和固定化酶催化反应的最适宜pH值分别为9.32和7.34,即固定化酶的最适宜pH值向酸性方向发生了移动,且适宜的pH值范围变大.游离酶催化反应的最适宜温度为50℃,在较低或较高的温度,其活性都低;而固定化酶的最适宜温度为40℃,且温度范围显著变宽,在(20～60)℃范围内,固定化酶都能保持较高的活性.固定化酶具有良好的连续操作稳定性,且比游离酶具有较好的抗金属离子性能;二者的米氏常数分别为2.38×10-1mol/L和5.44×10-2mol/L.Immobilized Penicillin acylase was prepared by using a novel composite support PEI/SIO2, the optimum pH and temperature of the free enzyme and immobilized enzyme were examined, and the continuous operation stability and the resistance to metal ions were studied. At the same time, Michaelis- Menten constants of the free enzyme and the immobilized enzyme were measured, respectively. The experiment results show that the optimum pHs of free enzyme and immobilized enzyme are 9. 32 and 7. 34. Respectively, the optimum pH of the immobilized enzyme is shifted to acidity and the range of the suitable pH is widened. The optimum temperature of the free enzyme is 50℃, and the catalysis activities are very low at lower or higher temperature. Whereas for the immobilized enzyme, optimum temperature is 40℃, the range of the suitable temperature is widened obviously, and higher activity always can be retained from 20℃ to 60℃. The immobilized.enzyme has better continuous operation stability and resistance to metal ions. Michaelis-Menten constants of the immobilized enzyme and the free enzyme are 2.38×10^-1 mol/L and 5. 44× 10^-2 mol/L, respectively.

关 键 词：复合载体 固定化 青霉素酰化酶 酶学性质 操作稳定性 米氏常数 

分 类 号：Q814[生物学—生物工程]