The putative
catalytic residues (Asp and Glu) are conserved between these
proteins, and at least four regions with a high degree of similarity
appear to be unique for this group of enzymes. These regions were
absent from T. reesei Cel3A, the main extracellular b-glucosidase
induced after exposure to cellulose, which is only for 38% identical
to the Aspergillus proteins. The expression profiles of the ten
b-glucosidase genes of T. reesei under cellulose-producing condition
were analyzed and compared to the expression levels of the
cellulase genes cbh1 and egl1 genes, encoding cellobiohydrolase I
and endoglucanase I, respectively