壳聚糖固定化蚯蚓纤溶酶及其性质

以壳聚糖为载体,戊二醛为交联剂,用吸附交联法固定蚯蚓纤溶酶,对蚯蚓纤溶酶的固定化条件及固定化酶的各种性质进行了研究,确定了酶固定的最适条件:1 g用pH为6.5的磷酸盐缓冲液浸泡的壳聚糖载体与5 mL体积分数为1%戊二醛在25℃交联8 h,充分洗去戊二醛之后,加入蚯蚓纤溶酶13 U,4℃吸附6 h,充分洗去未交联的游离酶,酶活力回收最高大约为63%,固定化酶的比活为0.082 U/mg.固定化酶,游离酶的最适温度均为50℃,游离酶的最适pH值为8.5,而固定化酶的最适pH值为8.0,固定化酶的热稳定性,pH稳定性均比游离酶有所提高,游离酶、固定化酶都能水解纤维蛋白原和纤维蛋白,固定化酶不再水解BSA.

Immobilization of Earthworm Fibrinolytie Enzymes on Chitosan

Carthworm fibrinolytic enzymes were immobilized on chitosan in glutaraldehyde by adsorb and cross-link reaction.The optimal conditions for immobilization were as follows:1 g chitosan with pH=6.5 phosphate buffer solution was treated with 5 mL 1% glutaraldehyde solution at 25 ℃ for 8 h,then 13 U earthworm fibrinolytic enzymes solution were added into after rinsing the chitosan thoroughly and adsorbed on the carrier at 4 ℃ for 6 h,after rinsing the unimmobilized enzymes with 1 mol/L NaCl,the enzyme activity recovery was about 63%,the activity of immobilized enzymes was 0.082 U/mg.The optimal temperature for free and immobilized enzymes were 50 ℃,their optimal pH were 8.5 and 8.0 respectively,the thermostability and the pH stability of immobilized enzymes were enhanced compared with free enzymes.The enzymes could hydrolyze fibrinogen and fibrin after being immobilized,however,the immobilized enzymes could not hydrolyze BSA any more.