基于Monte Carlo模拟的壳聚糖酶解与酸解产生低聚糖的比较

通过把降解对象由壳聚糖分子转化为糖苷键的方法，回避了枚举反应方程式的问题；使用Monte Carlo方法对壳聚糖的酶解与酸解进行了理论模拟。以六糖为目标产物的讨论表明，无论酸解或酶解，在反应起始阶段，六糖产率几乎相等；随反应的进行，明显的端基倾向或较高外切酶活性使六糖产率降低。在反应起始阶段，端基倾向明显或外切酶活性高将提高单糖与六糖的比例。酶法中可以通过添加内切酶的方法降低外切酶的影响，因此，酶法更适于制备低聚糖。

Comparison of Oligosaccharide Produced from Chitosan Degradation Catalysed by Acid or Enzyme Based on Simulation with Monte Carlo Method

Monte Carlo simulation of enzyme or acid catalyzed degradation of chitosan was carried out by taking glucose bonds instead of the whole chitosan molecule as a model, which avoided the difficulty of writing the complex chemical equations one by one. Regarding the hexasaccharide as the target product, results showed that proportion of hexasaccharide to products was similar in the early stage of both acid and enzyme catalyzed degradation. With the degradation going on, linkage-end-trend or exoglycosidase activity increasing caused the decrease of the proportion of hexsaccharide. However, the higher linkage-end-trend and higher exoglycosidase activity were,the higher proportion of monosaccharide to hexasaccharide was,even in the early degradation stage. It was concluded that the degradation catalyzed by enzyme was more suitable to produce oligomer since adding more endoglycosidase enzyme could decrease the exoglycosidase effect.