用CHITOSAN固定化青霉素酰化酶

本文报道以Chitosan为载体制备固定化青霉素酰化酶的研究结果。1.4％ Chitosan醋酸溶液先用12.5％戊二醛交联,洗涤,研磨,得颗粒。再用1.5％pH5.5和1.5％pH8.5多聚磷酸处理,得机械强度良好的载体。此载体先后经0.5％戊二醛和对甲苯磺酰氯双活化后,再与青霉素酰化酶偶联。所得固定化酶的活力达20.8u/g。固定化青霉素酰化酶的反应最适温度略高于游离酶,最适pH略低于游离酶;其Km值基本接近游离酶。固定化酶经反复使用,活力基本不变。

IMMOBILIZATION OF PENICILLIN ACYLASE ON CHITOSAN MATRIX

Study of immobilization of penicillin acylasc on chitosan matrix is reported.The chitosan matrix is prepared by first crosslinking of 1.4% chitosan solution with 12.5%glutaldehyde and then by tonotropic gelation with 1.5%pH 5.5 and 1.5% pH8.5 polyphosphoric acid solution, The chitosan matrix thus prepared is good in mechanical strength and easy to be filtered.The matrix is double activatd by 0.5%glutaldehyde and p-toluenesulfonyl chloride tosylation successively. The penicillin acylase is finally immobilized by coupling.The optimum temperature of the chitosan immobilizede enzyme is slightly higher than that of the free enzyme The optimum pH of the immobilized enzyme is slightly lower than that of the free enzyme, The Km of the free and immobilized penicillin acylase are 1.25 and 1.52 mM respectively. The actiyity of the immobilized enzyma remains unchanged after more than twenty cycles.