肝素修饰尿激酶某些性质的研究

本文对比研究了溴化氰活化及高碘酸活化肝素修饰的两种修饰尿激酶的性质。结果表明尿激酶在溴化氰活化肝素(肝素CN),高碘酸钠活化肝素(肝素I_4)的共价修饰后,其残余自由氨基分别是64％和52％;酶活性分别保留94％和90％;抗胃蛋白酶水解以及抗冻融变性的能力均高于天然酶;在离体血浆中的失活速变低于天然酶。本文还对修饰酶进行了萤光及紫外差光谱的分析,讨论了修饰过程对构象的影响。

Properties of the Urokinase Modified by Heparin

A comparison of urokinase modified by cyanogen bromide or sodium periodate activited heparin was made. The results showed that after covalent modification of urokinase with heparin-CN and heparin-IO4 the free amino groups remaining on the conjugates are 64% and 52% respectively, and retained 94% and 90% enzymatic activities of the native urokinasc. The ability of the conjugates to resist the hydrolysis by pepsin or trypsia as well as denaturation from freeze-thaw is higher than the native urokinase. The modified enzymes showed lower inactivation rates than that of the native urokinase in Blood plasma in vitro.We also investigated the fluorescent spectrum and differential ultraviolet spectrum for both the modified enzymes and the native one. The conformational changes occurred during the modification process are discussed.