三种形态的壳聚糖固定化脲酶的研究

Three Different Formed Chitosan for Immobilization of Urease

以戊二醛为交联剂制备了 3种固定化载体 ,即粉末状 (Ⅰ ) ,凝胶状 (Ⅱ ) ,海棉状 (Ⅲ ) ,并测定了固定化酶的特性 .结果显示 :固定化脲酶Ⅰ ,Ⅱ ,Ⅲ的最适 pH都是 6,而游离酶的最适pH为 7;固定化脲酶Ⅰ ,Ⅱ ,Ⅲ的最适温度分别为 5 5 ,5 5 ,45℃ ,游离酶为 5 0℃ ;固定化酶Ⅰ ,Ⅱ ,Ⅲ的表观米氏常数Km 分别为 2 .78,14.5 ,3 4.5mmol/L ,游离酶的Km 为 5 5 .5mmol/L .以上结果并结合固定化酶 pH耐受性及贮存稳定性可知 ,凝胶状 (Ⅱ )

Three different chitosan carriers were prepared using glutaraldehyde as cross-linking reagent. The characteristics of immobilized urease were determined. The results indicate: the optimal temperature of the three kinds of immobilized urease was 55℃,55℃,45℃,respectively, while it was 50℃ for the soluble urease; the optimal pH of the immobilized urease were all 6 and the soluble urease was 7; the K m value of the immobilized urease were 2.78,14.5,34.5 mmol/L, that of the free urease was 55.5 mmol/L. From the above results and storage stability of immobilized urease, the gelatinous chitosan is suitable enzyme immobilized carriers.