Modes of Action on Cotton and Bacterial Cellulose of a Homologous Endoglucanase-Exoglucanase Pair From Trichoderma Reesei

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacteria
  • Binding Sites
  • Cellulase / isolation & purification
  • Cellulase / metabolism*
  • Cellulose / metabolism*
  • Cellulose 1,4-beta-Cellobiosidase
  • Chromatography, Ion Exchange
  • Crystallization
  • Gossypium
  • Substrate Specificity
  • Trichoderma / enzymology*


  • Cellulose
  • Cellulase
  • Cellulose 1,4-beta-Cellobiosidase