The inorganic silica carrier was prepared by coprecipitation and used to immobilize threonine deaminase.The silica carrier was characterized by scanning electron microscopy.Then immobilization conditions were optimized with n(Si)∶n(N) at 1∶1,the concentration of silicic acid at 0.03 mol/L,the amount of enzyme at 0.16 mg/mL.The optimal pH of the immobilized enzyme and the free enzyme was both 9.0,the optimal temperature was 45 ℃.Furthermore,the immobilized enzyme was more stable than the free enzyme under the conditions of pH between 9.0 and 10.0,and temperature between 35 and 50 ℃.The Km value of the immobilized enzyme was 7.48 mmol/L,and the enzyme activity was maintained at 80% after 15 times of repeated application.The results suggested that the immobilized threonine deaminase prepared by bionic silica has high activity recovery,high mechanical strength and stable operation conditions.%通过共沉淀法制备无机氧化硅载体,然后将其应用到苏氨酸脱氨酶的固定化研究中.用扫描电子显微镜对氧化硅载体进行表征,优化了固定化条件,当n(Si):n(N)为1∶1、偏硅酸浓度为0.03 mol/L、酶添加量为0.16 mg/mL 时,固定化的效率最高.接着对固定化酶和游离酶的酶学性质进行了考察,结果发现:固定化酶和游离酶的最适pH都是9.0,最适温度都是45 ℃,而相对于游离酶,固定化酶在pH 9.0~10.0和温度35~50 ℃范围内稳定性更好.固定化酶的米氏常数为7.48 mmol/L,重复使用15次后,酶活力保持80%以上.说明仿生氧化硅制备的固定化苏氨酸脱氨酶具有酶活回收率高、力学强度高和操作稳定性好等优势.
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