Abstract
An assay system for cellulases which are active on microcrystalline cellulose (Avicel) has been designed, that is, the cellulase activity was effectively assayed in the presence of endo-glucanase and β-glucosidase. Using this system, two electrophoretically distinct cellulases, which are called FI-Avicelase and FIII-Avicelase, have been purified from the culture filtrate of Aspergillus aculeatus No. F-50 to homogeneity by DEAE- and SP-Sephadex column chromatographies, and gel filtration with Sephacryl S-200. The molecular weights of the FI- and FIII-Avicelases were estimated to be 109, 000 and 112, 000, respectively, and their isoelectric points to be 4.7 and 4.0. Both cellulases are glycoproteins containing 20 to 30% sugar, but they differ from each other in amino acid composition.
