重组人超氧化物歧化酶化学修饰的初步研究

A Preliminary Study on Chemical Modification of Recombinent Human Superoxide Dismutase

在高效表达重组人铜锌超氧化物歧化酶(rh Cu/Zn SOD),并纯化得到比活大于4000单位的 rh Cu/Zn SOD 纯品的基础上,采用活化酯法将聚乙二醇(PEG)与 rhCu/Zn SOD 交联,获得分子量约6万的 PEG-SOD 交联物.经 PEG 修饰的酶稳定性增强,表现为对酸、碱和热的耐受力均较未交联酶高.修饰酶的生物半衰期为15h,是天然酶的90倍,酶活性保留80%以上.还实验观察了修饰剂用量与修饰酶保留活性之间的关系.

To overcome several disadvantages of the use of superoxide dismutase(SOD)in its native form thesurface modification of therapeutically useful enzyme by covalent linkage of nontoxic,nonimmunogenic,and biocompatible polymers has been investigated.Recombinent human Cu/Zn SOD(rh Cu/Zn SOD)obtained from.E.coli was coupled chemically with activated polyethylene glycol(PEG).The modifiedrhCu/Zn SOD,with apparent molecular weight about 60000 daltons,has longer half-life(15 hours),and the remaining enzyme activity is more than 80 per cent.Its stabilities against acid,alkali and heatwere increased significantly.The relation between the amount of PEG used and the remained enzymeactivity was also reported.