Modes of action on cotton and bacterial cellulose of a homologous endoglucanase-exoglucanase pair from Trichoderma reesei

Malee Srisodsuk, Karen Kleman-Leyer, Sirkka Keränen, T. Kent Kirk, Tuula Teeri (Corresponding Author)

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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.
Original languageEnglish
Pages (from-to)885-892
JournalEuropean Journal of Biochemistry
Issue number3
Publication statusPublished - 1998
MoE publication typeA1 Journal article-refereed


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