Evolutionary molecular engineering and structure-activity relationship in cellulase condensation reaction.

来自丝状真菌里氏木霉（Trichoderma reesei）的内切葡聚糖酶I（EG I）尚未被认为水解“纤维二糖”。另一方面，分泌的β-葡萄糖苷酶I（BGL I）的生理作用尚不清楚，其可以在菌体外水解纤维二糖。T. reesei衍生的EG I（其催化结构域被使用）以底物浓度依赖性方式从纤维二糖（底物）生成葡萄糖（产物），并且在高底物浓度（例如1 M）下葡萄糖生成率达到BGL I的一半以上。当T. reesei来源的BGL I与高浓度的纤维二糖反应，观察到被认为是转糖基化产物的三糖的显著合成。在BGL I与高浓度葡萄糖反应的情况下，没有观察到缩合产物。BGL I在真菌体内的生理作用被认为与BGL II不同，据报道，BGL I通过体外高浓度葡萄糖的缩合产生最强的纤维素酶诱导剂槐糖。

Endoglucanase I(EG I) from filamentous fungus Trichoderma reesei has not been considered to hydrolyze the"cellobiose". On the other hand, the physiological role of a secretedβ-glucosidase I(BGL I) is not clear, which can hydrolyze cellobiose outside fungus body. T. reesei derived EG I, of which catalytic domain was used, generated glucose(product) from cellobiose(substrate) in a substrate concentration-dependent manner, and glucose production ratio reached to more than half of BGL I under the high substrate concentration such as 1 M. When T. reesei derived BGL I reacted with a high concentration of cellobiose, a remarkable synthesis of trisaccharide considered as transglycosylational product was observed. In the case that BGL I reacts with high concentrations of glucose, no condensational product was observed. The physiological role of BGL I is considered to be different to BGL II in the fungus body, which has been reported to generate the strongest cellulase inducer sophorose by the in vitro condensation of high concentration of glucose.