壳聚糖修饰羊毛防毡缩用蛋白酶的制备及其酶学性质

Preparation of Chitosan Conjugated Protease Used for Shrink Resistance of Wool and Its Properties

为了减少防毡缩整理中蛋白酶对羊毛纤维主体结构的破坏作用,利用水溶性碳二亚胺将壳聚糖大分子偶联到蛋白酶(Savinase 16L)分子上,增大蛋白酶分子量,从而将水解作用限制在纤维表面。研究结果表明,壳聚糖修饰后蛋白酶的二级结构更加规整,整体结构更加紧凑;Km从20.62g/L提高到35.21g/L,表明其对底物的亲和力变小;修饰酶的最适温度为55℃,在该温度下的热稳定性较好,且在70℃以上的高温下,修饰酶显示出优于未修饰酶的稳定性。

Chitosan was covalently coupled to protease(Savinase 16L) with water-soluble carbodiimide to enlarge its molecular weight,with the purpose of reducing enzymatic damage to wool fibres in anti-felting finishing.It was found that the secondary and the whole structures of the modified protease were much more regular and compact than the native one.The conjugated protease presented a lower affinity towards casein with an increase in Km from 20.62 g/L to 35.21 g/L.There was no change in optimum temperature(55 ℃)for the modified protease while its thermal stability at 55 ℃ was improved.Compared to the native enzyme,the modified protease displayed higher stability above 70℃.