Srisodsuk M, Kleman-Leyer K, Keränen S, Kirk T K, Teeri T T
VTT Biotechnology and Food Research, Finland.
Eur J Biochem. 1998 Feb 1;251(3):885-92. doi: 10.1046/j.1432-1327.1998.2510885.x.
The endoglucanase I (EGI) and the cellobiohydrolase I (CBHI) of the filamentous fungus Trichoderma reesei form a homologous pair of cellulolytic enzymes which nevertheless have different modes of action. We show here that the action of CBHI on bacterial microcrystalline cellulose results in efficient solubilisation but only a slow decrease in its degree of polymerisation. In contrast, the action of EGI results in a rapid decrease of the degree of polymerisation but less efficient overall solubilisation of the substrate. CBHI alone was practically inactive toward cotton which has a high initial degree of polymerisation and a complex morphology. EGI rapidly reduced the degree of polymerisation of cotton, and slowly solubilised part of it. Working synergistically, EGI and CBHI solubilised cotton more rapidly and to a greater extent than EGI alone. Our data are consistent with the exoglucanase nature of CBHI and also provide some evidence supporting its processive mode of action.
丝状真菌里氏木霉的内切葡聚糖酶I（EGI）和纤维二糖水解酶I（CBHI）构成一对同源的纤维素分解酶，但它们具有不同的作用方式。我们在此表明，CBHI作用于细菌微晶纤维素可实现高效溶解，但其聚合度仅缓慢降低。相比之下，EGI的作用会导致聚合度迅速降低，但底物的总体溶解效率较低。单独的CBHI对具有高初始聚合度和复杂形态的棉花几乎没有活性。EGI迅速降低了棉花的聚合度，并缓慢溶解了其中一部分。EGI和CBHI协同作用时，比单独的EGI更迅速且更大量地溶解了棉花。我们的数据与CBHI的外切葡聚糖酶性质一致，也提供了一些证据支持其连续作用模式。
