Enzymatic Hydrolysis of Cellulose with Different Crystallinities Studied by Means of SEC-MALLS

The reactions of exo-cellulase （cellobiohydrolase, CBH） and endo-cellulase （endoglucanase, EG） were investigated by analyzing the insoluble residues of microcrystalline cellulose （MCC） and filter paper cellulose （FPC） during enzymatic hydrolysis. Molecular parameters including molecular weight and its distribution, degree of polymerization, and radii of gyration were measured by size exclusion chromatography coupled with multi-angle laser light scattering. No significant change in MCC chains was found during the whole reaction period, indicating that CBH digestion follows a layer-by-layer solubilization manner. This reaction mode might be the major reason for slow enzymatic hydrolysis of cellulose. On the other hand, the degree of polymerization of FPC chains decreases rapidly in the initial reaction, indicating that EG digestion follows a random scission manner, which may create new ends for CBH easily. The slopes of the conformation plots for MCC and FPC increase gradually, indicating stronger chain stiffness of cellulose during hvdrolvsis

exo 绗维素酶的反应(cellobiohydrolase， CBH ) 并且 endo 绗维素酶(endoglucanase，例如) 被在酶的水解作用期间分析微晶质的纤维素(MCC ) 和过滤器纸纤维素(FPC ) 的不可溶解的残余调查。包括分子的重量和它的分发，聚合的度，和旋转的半径的分子的参数被排除层析结合了多角度激光光散布的尺寸测量。在 MCC 链的重要变化都没在整个反应时期期间被发现，显示那 CBH 消化跟随一种 layer-by-layer 增溶方式。这个反应模式可能是为纤维素的慢酶的水解作用的主要原因。在另一方面， FPC 的聚合的度在起始的反应很快锁住减少，显示例如，消化跟随一种随机的切断方式，它可以容易为 CBH 创造新结束。为 MCC 和 FPC 的符合构造阴谋的斜坡逐渐地增加，显示在水解作用期间的纤维素的更强壮的链僵硬。