海藻糖对脂肪酶的保护机理及酶失活动力学

采用自制的磁性固定化酶(MIE),考察了高温下二糖类对酶的保护作用。结果显示:海藻糖对悬浮于水溶液中的MIE没有保护作用;而在高温干燥后,对酶的保护作用效果依次为:海藻糖>乳糖>蔗糖,支持‘玻璃态学说’;此外,采用两步失活动力学模型能够较好的拟合酶的失活过程,并且得到酶的失活速率常数k和半衰期t1/2,加入海藻糖和乳糖之后,MIE的半衰期分别增长了31和23倍。

Protection mechanism of Candida rugosa lipase by trehalose and its deactivation kinetics

Candida rugosa lipase was immobilized onto magnetic nanoparticles by covalent attachment.The protection of the immobilized lipase by disaccharides(trehalose,lactose,sucrose) was investigated.It was showed that trehalose could not reduce the activity lost of MIE in solution.On the other hand,the stability of MIE increased in the presence of trehalose during drying and storage.Furthermore,on the preservation of protein native structure,trehalose was more efficient than lactose,and sucrose showed little effect on the enzyme protection.This is because the glass transition temperature of trehalose is higher than that of lactose and sucrose.That is,the increased stability of the MIE is because of the formation of a glassy state in and around enzyme molecules.In addition,thermal deactivation kinetics of MIE was analyzed in the absence and in the presence of trehalose and lactose.Suitable mechanism was proposed to describe the deactivation process.In the presence of trehalose and lactose,the MIE half-lives increased 31-and 23-fold,respectively.