title: Modes of action on cotton and bacterial cellulose of a homologous endoglucanase-exoglucanase pair from Trichoderma reesei.
abstract: 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.
authors.affiliation: VTT Biotechnology and Food Research, Finland.
authors.forename: M
authors.initials: M
authors.lastname: Srisodsuk
authors.forename: K
authors.initials: K
authors.lastname: Kleman-Leyer
authors.forename: S
authors.initials: S
authors.lastname: Keränen
authors.forename: T K
authors.initials: TK
authors.lastname: Kirk
authors.forename: T T
authors.initials: TT
authors.lastname: Teeri
mesh_terms: D001419:Bacteria; D001665:Binding Sites; D002480:Cellulase / Q000302:isolation & purification / Q000378:metabolism*; D002482:Cellulose / Q000378:metabolism*; D043366:Cellulose 1,4-beta-Cellobiosidase; D002852:Chromatography, Ion Exchange; D003460:Crystallization; D003368:Gossypium; D013379:Substrate Specificity; D014242:Trichoderma / Q000201:enzymology*
chemical_list: D002482:Cellulose; D002480:Cellulase; D043366:Cellulose 1,4-beta-Cellobiosidase