Enzymic Properties of Three β-Glucosidases fromAspergillus aculeatusNo. F-50

Abstract

The enzymic properties of three electrophoretically distinct β-glucosidases, β-glucosidase-1, -2 and -3, from Aspergillus aculeatus No. F-50 were investigated. β-Glucosidase-3 had a low optimum pH of 3.0, but the other two enzymes had optimum pHs of 4.0~4.5. Both β-glucosidase-1 and -2 were potently active not only on soluble cellooligosaccharides, such as cellotriose to cellohexaose, but also on insoluble cellooligosaccharide, of which the average degree of polymerization was 20. On the contrary, β-glucosidase-3 was only slightly active on the insoluble substrate. The combined use of either β-glucosidase-1 or -2 and endo-glucanase remarkably stimulated the hydrolysis of amorphous cellulose, yielding glucose only. But β-glucosidase-3 did not show such a synergistic effect, and the glucose content of the hydrolyzate was only about 60%.