季铵化壳聚糖对超氧化物歧化酶的化学修饰研究

Chemical Modification of Superoxide Dismutase with N-trymethyl Chitosan

目的用季铵化壳聚糖(TMC)化学修饰超氧化物歧化酶(Cu,Zn-SOD),并研究修饰酶(TMC-SOD)的理化性质,以期获得高等电点的酶。方法用1-(3-二甲氨基丙基)-3-乙基碳二亚胺盐酸盐(EDC.HCl)作为交联剂,用TMC对Cu,Zn-SOD化学修饰,得到TMC-SOD共价复合物。IEF-PAGE法测定其等电点分布;用水浴考察其耐热能力。结果 TMC成功修饰Cu,Zn-SOD;修饰酶经过凝胶层析收集到3个活性峰,修饰酶等电点、耐热能力均提高。结论 TMC修饰SOD能够提高SOD热稳定性、阳电荷性。

OBJECTIVE To chemically modify superoxide dismutase（Cu,Zn-SOD） with N-trymethyl chitosan（TMC） in order to get this enzyme with higher isoelectric point,and to study the physical and chemical properties of the modified enzyme（TMC-SOD）.METHODS Cu,Zn-SOD was modified with TMC using 1-ethyl-3-（3-dimethylaminopropyl） carbodiimide（EDC） as coupling agent.The isoelectric point of the modified enzyme was measured by gel filtration chromatography and IEF-PAGE,and the thermal stability of Cu,Zn-SOD（TMC-SOD） was studied under high temperature in water bath.RESULTS Cu,Zn-SOD was successfully modified by TWC.Employing gel chromatography,3 activie peaks were collected from the modified SOD.The modified SOD had higher isoelectric point and thermostability than native SOD.CONCLUSION TMC can he used to modify SOD to increase its thermostability and positive charge.