M. Legisa et M. Bencina, EVIDENCE FOR THE ACTIVATION OF 6-PHOSPHOFRUCTO-1-KINASE BY CAMP-DEPENDENT PROTEIN-KINASE IN ASPERGILLUS-NIGER, FEMS microbiology letters, 118(3), 1994, pp. 327-333
The change from pentose phosphate pathway to glycolysis plays a signif
icant role in the physiology of Aspergillus niger during the induction
of citric acid accumulation. Evidence is shown for the importance of
6-phosphofructo-1-kinase in this process since it is activated by phos
phorylation. By incubating a purified active form of the enzyme togeth
er with commercially available alkaline phosphatase, 6-phosphofructo-1
-kinase activity was lost after a certain time suggesting that the enz
yme was dephosphorylated. Inactive 6-phosphofructo-1-kinase could be i
solated from the cells in the early stage of growth in a high citric a
cid yielding medium. The enzyme was 'in vitro' activated by isolated p
rotein kinase in the presence of cAMP, ATP and Mg2+ ions. Additional e
vidence for covalent phosphorylation of inactive 6-phosphofructo-1-kin
ase was obtained by incubating both enzymes together with labelled [ga
mma-P-32]ATP. The activating enzyme was partially purified from A. nig
er mycelium.