提高α-半乳糖苷酶稳定性的研究

研究了臭曲霉ZU—Gl产α-半乳糖苷酶的热稳定性提高方法及其相应措施。针对提高α-半乳糖苷酶制剂热稳定性的问题,研究了添加物质对酶热稳定性的影响。结果表明,甘露醇对α-半乳糖苷酶的保护效果最好,其次是棉籽糖、海藻糖和蜜二糖;L-半胱氨酸、黄原胶和甘油也起到了较好的保护作用。采用正交实验设计优化出最佳保护剂配方,即1.75mmol/L的海藻糖,1.5mmol/L的甘露醇和2mmol/L的棉籽糖。复合保护剂的添加使α-半乳糖苷酶在30～60℃时酶活保留率提高11.6%～21.7%;在pH3.0时酶活保留率提高52%。α-半乳糖苷酶在28℃、36.2℃和45℃下贮存,添加保护剂组酶活损失50%的时间分别为89.5d、38.4d和8.4d,对照组分别为40.9d、23.3d和7.79d。

Method for Increasing Stability of α-Galactosidase

This study was to investigate the methods of increasing the thermostability ofα-galactosidase from Aspergillus foetidus ZU-G1.In order to increaseα-galaetosidase heat stability,effect of different pro- tectors was studied.The result demonstrated that mannitol was the best protective substance,followed by raffinose,trehalose and melibiose,L-cysteine,xanthan gum and glycerol showed slightly protective ability. The best formula of different protectors optimized by orthogonal experiment design consist of trehalose 1.75 mmol/L,mannitol 1.5 mmol/L and raffinose 2.0 mmol/L.The residual activity ofα-galactosidase prepara- tion containing multiplex protectors was increased by 11.6%～21.7% at 30～60℃,and the residual activity at pH 3.0 was increased by 51.6%.The half-life of preparation containing multiplex protectors was 89.5 days,38.4 days and 8.4 days at 28℃,36.2℃and 45℃,respectively;the controlled ones was 40.9 days, 23.3 days and 7.8 days,respectively.