Production and catabolite repression of Penicillium italicum beta-glucanases.
AUTOR(ES)
Santos, T
RESUMO
The filamentous fungus Penicillium italicum, grown in a defined liquid medium, produced beta-1,3-glucanase, which remained essentially bound to the cells, and beta-1,6-glucanase, an essentially extracellular enzyme. When glucose was depleted from the medium, when a limited concentration of glucose (0.2%) was maintained, or when the carbon source was galactose (3%) or lactose (3%), a significant increase in the specific activity of beta-1,3-glucanase, in cell extracts, took place. This was paralleled by a very slow rate of growth, and under glucose limitation, the appearance of beta-1,3-glucanase in the medium was also observed. On the other hand, when an excess of glucose, fructose, or sucrose was present, the specific activity remained constant and active growth was promoted. Laminarin, cellobiose, gentiobiose, and isolated Penicillium italicum walls were not capable of significantly inducing beta-1,3-glucanase synthesis to a level beyond that attained by glucose limitation. A similar behavior was observed for beta-1,6-glucanase. beta-1,3-Glucanase and beta-1,6-glucanase are therefore constitutive enzymes subjected to catabolite repression. The results are discussed in the context of the possible functions that have been suggested for glucanases and related enzymes.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=234893Documentos Relacionados
- Repression of endo-1,4-beta-glucanase formation in Penicillium janthinellum and product inhibition of its 1,4-beta-glucanases and cellobiases.
- Distribution of beta-glucanases within the genus Bacillus.
- Derepression of beta-1,3-glucanases in Penicillium italicum: localization of the various enzymes and correlation with cell wall glucan mobilization and autolysis.
- Regulation of the beta-1,3-glucanase system in Penicillium italicum: glucose repression of the various enzymes.
- Separation and characterization of six (1 leads to 3)-beta-glucanases from Saccharomyces cerevisiae.