In:
Canadian Journal of Microbiology, Canadian Science Publishing, Vol. 44, No. 1 ( 1998-01-01), p. 6-11
Abstract:
The biosynthesis and role of fructose 2,6-bisphosphate (Fru-2,6-P 2 ) in carbohydrate metabolism during induction of an amylolytic system in Aspergillus oryzae was studied. Fluctuations in Fru-2,6-P 2 were not dependent on the external glucose concentration during induction, whereas the level of Fru-2,6-P 2 increased significantly when the oxygen concentration was diminished. Phosphofructokinase II (PFK II) of A. oryzae was sensitive to phosphorylation in vitro by the catalytic subunit of cyclic AMP dependent protein kinase, which increased the V max (twofold), although the K m (0.7 mM) remained unchanged. Phosphofructokinase I was neither activated by micromolar Fru-2,6-P 2 nor inhibited by high ATP concentrations. The activity of fructose-1,6-bisphosphatase (FBPase) was subject to strong inhibition by Fru-2,6-P 2 . Addition of glucose to cultures under gluconeogenic conditions caused a decrease of approximately 40% in the FBPase activity within 4 min. These results indicate that the effect of Fru-2,6-P 2 in A. oryzae could preferentially control gluconeogenesis. The addition of 0.1 M glucose under gluconeogenic culture conditions also showed that Fru-2,6-P 2 fluctuations appeared to be, at least in short term, more closely related to temporal changes in the hexose-6-phosphate concentration.Key words: Aspergillus oryzae; fructose-2,6-bisphosphate; phosphofructokinase II (PFK II); cyclic AMP; gluconeogenesis control.
Type of Medium:
Online Resource
ISSN:
0008-4166
,
1480-3275
Language:
English
Publisher:
Canadian Science Publishing
Publication Date:
1998
detail.hit.zdb_id:
280534-0
detail.hit.zdb_id:
1481972-7
SSG:
12
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