THE FORMATION OF N-ACETYL-BETA-D-HEXOSAMINIDASE IS REPRESSED BY GLUCOSE IN PENICILLIUM-CHRYSOGENUM

The formation of N-acetyl-beta-D-hexosaminidase is under carbon catabo lite repression in growing Penicillium chrysogenum. The enzyme accumul ates inside the cells during the stationary phase of growth and is rel eased into the culture fluid when the cell-wall lysis has started and progressed. The time-course of enzyme formation strongly supports the suggestion that fungal N-acetyl-beta-D-hexosaminidase may have a role in the degradation of intermediate cell-wall breakdown products during starvation. Regarding that analogous enzymes from other fungi have be en shown to be able to liberate GlcNAc monomers from different glycopr oteins and glycopeptides a possible participation in the orderly destr uction of cellular glycoprotein components cannot be excluded. The phy sical and enzyme kinetic properties of both intracellular and extracel lular N-acetyl-beta-D-hexosaminidase are essentially the same indicati ng that the enzyme is probably released into the culture fluid without modification.