Formation, Location, and Regulation of Endo-1,4-β-Glucanases and β-Glucosidases from Cellulomonas uda

Abstract

The formation and location of endo-1,4-β-glucanases and β-glucosidases were studied in cultures of Cellulomonas uda grown on microcrystalline cellulose, carboxymethyl cellulose, printed newspaper, and some mono- or disaccharides. Endo-1,4-Glucanases were found to be extracellular, but a very small amount of cell-bound endo-1,4-β-glucanase was considered to be the basal endoglucanase level of the cells. The formation of extracellular endo-1,4-β-glucanases was induced by cellobiose and repressed by glucose. Extracellular endoglucanase activity was inhibited by cellobiose but not by glucose. β-Glucosidases, on the other hand, were formed constitutively and found to be cell bound. β-Glucosidase activity was inhibited noncompetitively by glucose. Some characteristics such as the optimal pH for and the thermostability of the endoglucanases and β-glucosidases and the end products of cellulose degradation were determined.