添加剂对漆酶酸碱稳定性的影响及保护机理

Effect and protection mechanism of additives on acid-base stability of laccase

为了提高漆酶的稳定性,研究了甘油、肌醇和山梨醇3种添加剂对漆酶酸碱稳定性的影响,并通过紫外光谱、荧光光谱和圆二色谱分析了添加剂对漆酶的保护机理。研究表明,添加剂对漆酶的保护效果与添加剂的种类和浓度有关。在p H 3的缓冲液中,当肌醇的浓度为0.2 mol/L时漆酶的相对酶活达到最大值(125%),当甘油或山梨醇浓度增加时,漆酶的相对酶活逐渐增大;当添加的浓度相同时,甘油对漆酶的保护效果强于山梨醇,当添加的浓度为0.6 mol/L时,甘油使漆酶相对酶活提高了29%,山梨醇使漆酶相对酶活提高了15%。漆酶适宜的p H值范围为2~5,加入添加剂后提高了漆酶的酸碱稳定性。通过光谱分析可知,通过与漆酶分子间形成氢键,甘油、肌醇和山梨醇可以提高漆酶在溶液中的酸碱稳定性。

In order to improve the stability of laccase,the effects of three additives（ glycerol,inositol and sorbitol） on the acid-base stability of laccase were studied,and the protection mechanism of the additives on laccase was analyzed by UV spectroscopy,fluorescence spectroscopy and circular dichroism. The results indicated that the protective effect of the additives on laccase was related to the type and concentration of the additives. When the concentration of inositol was 0. 2 mol/L in buffer at pH = 3,the relative activity of laccase reached the maximum（ 125%）.With increasing of the concentration of glycerol or sorbitol,the relative activity of laccase increased gradually. When the concentration was 0. 6 mol/L,glycerol increased the relative activity of laccase by 29%,and sorbitol increased the relative activity of laccase by 15%. The optimum p H range for laccase should be p H 2 to 5,and use of additives could improve the acidity of laccase. Spectral analysis showed that these additives could form hydrogen bonds with laccase molecules in the solution,resulting in the improvement on the acid-base stability of laccase.