Abstract
Three electrophoretically distinct β-glucosidases, β-glucosidase-1, -2 and -3, have been purified from a culture filtrate of Aspergillus aculeatus No. F-50 to homogeneity by ethanol fractionation, DEAE- and SP-Sephadex column chromatography, gel filtration with Sephacryl S-200 and isoelectric focusing. Both β-glucosidase-1 and -2 were potently active not only on salicin but also on insoluble cellooligosaccharide, of which the average degree of polymerization was 20. On the other hand, β-glucosidase-3 was only slightly active on the latter substrate. The molecular weights of β-glucosidase-1, -2 and -3 were estimated to be 133, 000, 132, 000 and 136, 000, respectively, and their isoelectric points to be 4.7, 4.3 and 3.5. All the β-glucosidases were rich in acidic amino acids and glycine, and were glycoproteins.
