Aging of Penicillium chrysogenum cultures under carbon starvation. II. Protease and N-acetyl-beta-D-hexosaminidase production
1997
Pusztahelyi, T. | Pocsi, I. | Szentirmai, A.
In aging carbon-depleted cultures of Penicillium chrysogenum the fragmentation and autolysis of old mycelia were coupled with the production of high levels of extracellular protease and N-acetyl-beta-D-hexosaminidase; this could be stopped by the addition of an extra dose of glucose at any incubation time tested, but was not affected by endogenous NH3. After the addition of glucose, intracellular enzyme accumulation was observed only for the N-acetyl-beta-D-hexosaminidase, and the concomitant decrease in both the extracellular protease and N-acetyl-beta-D-hexosaminidase activities was not caused by the action of extracellular proteases. The physiological function of the N-acetyl-beta-D-hexosaminidase remains to be elucidated because the P. chrysogenum culture studied did not utilize N-acetyl-D-glucosamine as a carbon source. However, the proteases (mainly serine and, to a much smaller extent, metalloproteases) might provide surviving hyphal fragments with sufficient amino acids to maintain the cryptic growth observed in aging carbon-depleted cultures.
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