Characterization of Endo-β-1, 4-Glucanase and β-Glucosidase from Aspergillus sp. K-27

Abstract

Endo-β-1, 4-glucanase and β-glucosidase from Aspergillus sp. K-27 were purified to homogeneity. Endo-β-1, 4-glucanase was a monomeric enzyme with a Mr of .21, 000. Its activities for cellooligosaccharides were high in the order of cellohexaose>cellopentaose>cellotetraose, but no activity was recorded in cellobiose or cellotriose. It degraded carboxymethyl cellulose into cellobiose very well; however, almost no action was recorded on Avicel. β-Glucosidase was shown to be composed of two subunits of different molecular weights (Mr 130, 000 and 105, 000). The activities of the enzyme for different disaccharides were in the order of laminaribiose (β-1, 3) >gentiobiose (β-1, 6) >cellobiose (β-1, 4) > sophorose (β-1, 2). Using cellooligosaccharides as substrates, the enzyme was shown to have the largest and smallest Km/ Vmax values for cellotriose and cellobiose, respectively.