Partially purified fructose-6-P,2-kinase:fructose-2,6-bisphosphatase from beef heart was phosphorylated by cAMP protein kinase. The phosphorylated fructose-6-P,2-kinase shows lower K(m) for Fru-6-P (43 versus 105 μM) and for ATP (0.55 versus 1.3 mM) but no change in the V(max), compared to those for unphosphorylated enzyme. There was no detectable change in K(m) or V(max) of fructose-2,6-bisphosphatase activity by the phosphorylation. These changes in heart fructose-6-P,2-kinase were in direct contrast to previous results for the liver isozyme in which phosphorylation led to inhibition of the kinase activity and activation of the phosphatase activity.
|Original language||English (US)|
|Number of pages||3|
|Journal||Journal of Biological Chemistry|
|State||Published - 1987|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology