Regulation of beta-glucosidase biosynthesis in Aspergillus nidulans

beta-Glucosidase in Aspergillus nidulans was found to be both intracellular and extracellular. The intracellular beta-glucosidase was synthesized after the exhaustion of carbon source in the medium. The extracellular enzyme appeared with autolysis of the mycelium. Biosynthesis of beta-glucosidase was not induced by various carbohydrates but repressed to varying extents in the presence of glucose, glycerol, and 2-deoxyglucose. This repression was not relieved by addition of cAMP. The repression was relieved much more by mutations in the creA gene than by one in the creC gene. Thus, beta-glucosidase synthesis in A. nidulans is subject to carbon catabolite repression.