Regulation of phosphofructokinase at physiological concentration of enzyme studied by stopped-flow measurements.
Stopped-flow measurements have been carried out to study some basic allosteric properties of muscle and yeast phosphofructokinase at physiological concentration of enzyme. An important increase in the affinity for fructose-6-P accompanied by an intense decrease in the ATP inhibition was observed with the muscle enzyme, which also became insensitive to fructose-2,6-P2 under these conditions. Yeast phosphofructokinase exhibited a significant diminution in the inhibition by ATP, although with no apparent change in the affinity for fructose-6-P. These results provide strong support in favor of the dependence of the allosteric regulation of phosphofructokinase on its concentration in vivo.
Bär
J
J
Institut für Biochemie, Bereich Medizin, Karl-Marx-Universität, Leipzig, German Democratic Republic.
Martínez-Costa
O H
OH
Aragón
J J
JJ
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D005635:Fructosediphosphates / Q000494:pharmacology; D006706:Homeostasis; D007700:Kinetics; D009132:Muscles / Q000201:enzymology; D010732:Phosphofructokinase-1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011817:Rabbits
D005635:Fructosediphosphates; D000255:Adenosine Triphosphate; D010732:Phosphofructokinase-1; C029063:fructose-1,6-diphosphate