Evidence for the activation of 6-phosphofructo-1-kinase by cAMP-dependent protein kinase in Aspergillus niger |
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Authors: | Matic Legia Mojca Benina |
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Institution: | National Institute of Chemistry, Hajdrihova 19, SLO-61115 Ljubljana, Slovenia |
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Abstract: | Abstract The change from pentose phosphate pathway to glycolysis plays a significant role in the physiology of Aspergillus niger during the induction of citric acid accumulation. Evidence is shown for the importance of 6-phophofructo-1-kinase in this process since it is activated by phosphorylation. By incubating a purified active form of enzyme together with commercially available alkaline phosphatase, 6-phosphofructo-1-kinase activity was lost after a certain time suggesting that the enzyme was dephosphorylated. Inactive 6-phosphofructo-1-kinase could be isolated from the cells in the early stage of growth in a high citric acid yielding medium. The enzyme was 'in vitro' activated by isolated protein kinase in the presence of cAMP, ATP and Mg2+ ions. Additional evidence for covalent phosphorylation of inactive 6-phosphofructo-1-kinase was obtained by incubating both enzymes together with labelled γ ?32P]ATP. The activating enzyme was partially purified from A. niger mycelium. |
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Keywords: | Aspergillus niger 6-Phosphofructo-1-kinase cAMP-dependent protein kinase |
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