青霉素G酰化酶在磁性复合载体上的固定化及其酶学性质

利用凝胶-溶胶方法对磁性Fe3O4微粒表面进行功能化修饰,制备了表面含氨丙基的磁性复合载体,并通过戊二醛交联制备固定化青霉素G酰化酶(PGA).结果表明,在37℃时,固定化酶水解青霉素G钾盐,制备6-氨基青霉烷酸的表观活性为1 886 IU/g,表观米氏常数K'm＝140 mmol/L,最大反应速度Vmax＝0.45 ...

Immobilization and Enzymological Property of Penicillin G Acylase Immobilized on the Magnetic Composite Support

The magnetic composite support with a saturation magnetization value of 27.2 A · m^2 · kg^-1 was prepared via the sol-gel. The amino groups existing on the magnetic composite carrier could couple penicillin G acylase （PGA） by cross-linking with glutaraldehyde to form the immobilized enzyme. The catalytic performances of the immobilized PGA for hydrolyzing penicillin G potassium to produce 6- aminopenicillanic acid were studied. The apparent activity of the immobilized PGA was 1886 IU/g. The optimal temperature and the optimal pH were 50 ℃ and 7.0-8.0 for the hydrolysis reaction, respectively. The apparent Michaelis constant KIm and Vmax of the immobilized PGA were 240 mmol/L and 0.45 mmol/min, respectively. It was found that the thermal stability and the durability on acidic or basic medium of PGA immobilized the magnetic composite support increased greatly compared with those of the free enzyme, and its activity keeps 82.0% of its original activity after used 10 cycles. The immobilized PGA can be sedimentated fleetly in magnetic field and separated facilely from the product in applications.