Abstract: Savinase was modified with dextran via click chemistry so as to enlarge the molecular weight, which can be applied for shrink resistance of wool. The structure changes of modified Savinase were assessed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), circular dichroism (CD) and fluorescence spectroscopy. Enzymatic properties and kinetic parameters were also determined. The results indicated that the molecular weight of the modified Savinase was significantly increased. After modification, the secondary structure of enzyme changed and the substrate affinity lowered, while the effects of temperature and pH on enzyme activities were similar. For the shrink-resistance finishing of wool, it could be found that the wool fabric treated by modified Savinase could meet the machine-washable standard with obviously decreased strength loss.

Key words: protease, dextran, click chemistry, chemical modification, shrink resistance of wool