Abstract
Pyrophosphate : fructose-6-phosphate phosphotransferase (PPi-PFK) has been purified 150-fold from potato tubers and the kinetic properties of the purified enzyme have been investigated both in the forward and the reverse direction. Saturation curves for fructose 6-phosphate and also for fructose 1,6-bisphosphate were sigmoidal whereas those for PPi and Pi were hyperbolic. In the presence of fructose 2,6-bisphosphate, the affinity for fructose 6-phosphate and for fructose 1,6-bisphosphate were greatly increased and the kinetics became Michaëlian. The effect of fructose 2,6-bisphosphate was increased by the presence of fructose 6-phosphate and decreased by the presence of Pi. Consequently, the Ka for fructose 2,6-bisphosphate was as low as 5 nM for the forward reaction and reached 150 nM for the reverse reaction. On the basis of these properties, a procedure allowing one to measure fructose 2,6-bisphosphate in amounts lower than a picomole, is described.
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Claims 10
Claim · model-written summary
Potato tuber PPi-PFK was purified 150-fold.
Solanum tuberosumOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PPi-PFK) has been purified 150-fold from potato tubers”
Claim · model-written summary
Fructose 6-phosphate and fructose 1,6-bisphosphate saturation curves were sigmoidal.
- Outcome
- Saturation curves for fructose 6-phosphate and also for fructose 1,6-bisphosphatee0
Not reportedTaxonDirection
Verbatim
e0“Saturation curves for fructose 6-phosphate and also for fructose 1,6-bisphosphate were sigmoidal”
Claim · model-written summary
PPi and Pi saturation curves were hyperbolic.
- Outcome
- those for PPi and Pi were hyperbolice0
Not reportedTaxon
Verbatim
e0“those for PPi and Pi were hyperbolic”
Claim · model-written summary
Fructose 2,6-bisphosphate greatly increased affinity for fructose 6-phosphate and fructose 1,6-bisphosphate.
- Treatment
- fructose 2,6-bisphosphatee0
- Outcome
- affinity for fructose 6-phosphate and for fructose 1,6-bisphosphatee0
- Direction
- increasede0
Not reportedTaxonComparator
Verbatim
e0“In the presence of fructose 2,6-bisphosphate, the affinity for fructose 6-phosphate and for fructose 1,6-bisphosphate were greatly increased”
Claim · model-written summary
Fructose 2,6-bisphosphate made the kinetics Michaëlian.
Not reportedTaxonComparatorDirection
Verbatim
e0“In the presence of fructose 2,6-bisphosphate, the affinity for fructose 6-phosphate and for fructose 1,6-bisphosphate were greatly increased and the kinetics became Michaëlian”
Claim · model-written summary
Fructose 6-phosphate increased the effect of fructose 2,6-bisphosphate.
Not reportedTaxonComparator
Verbatim
e0“The effect of fructose 2,6-bisphosphate was increased by the presence of fructose 6-phosphate”
Claim · model-written summary
Pi decreased the effect of fructose 2,6-bisphosphate.
Not reportedTaxonComparator
Verbatim
e0“decreased by the presence of Pi”
Claim · model-written summary
The forward-reaction Ka for fructose 2,6-bisphosphate was as low as 5 nM.
Not reportedTaxon
Verbatim
e0“Ka for fructose 2,6-bisphosphate was as low as 5 nM for the forward reaction”
Claim · model-written summary
The reverse-reaction Ka for fructose 2,6-bisphosphate reached 150 nM.
Not reportedTaxon
Verbatim
e0“reached 150 nM for the reverse reaction”
Claim · model-written summary
The described procedure can measure less than a picomole of fructose 2,6-bisphosphate.
Verbatim
e0“a procedure allowing one to measure fructose 2,6-bisphosphate in amounts lower than a picomole”