Regulation of glycolysis in lizards: kinetic studies on liver pyruvate kinase and phosphofructokinase from Lacerta galloti.
Kinetic studies were carried out on pyruvate kinase and phosphofructokinase from the lizard Lacerta galloti. Pyruvate kinase is inhibited by ATP and activated by fructose 1,6-biphosphate giving an hyperbolic saturation curve for ATP without the activator which becomes sigmoidal at saturating concentrations of fructose 1,6-biphosphate, giving a moderate cooperativity with a Hill coefficient of h = 1.72. Binding of fructose 1,6-biphosphate to pyruvate kinase was studied as protection effect against thermal denaturation, this being the most suitable ligand tested to avoid the loss of activity. Phosphofructokinase is inhibited by ATP at millimolar range and activated by AMP and by fructose 2,6-biphosphate, AMP being the more efficient activator.
D000249:Adenosine Monophosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D005635:Fructosediphosphates / Q000494:pharmacology; D006019:Glycolysis; D007700:Kinetics; D008099:Liver / Q000378:metabolism; D008116:Lizards / Q000378:metabolism*; D008297:Male; D010732:Phosphofructokinase-1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011770:Pyruvate Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism*
D005635:Fructosediphosphates; D000249:Adenosine Monophosphate; D000255:Adenosine Triphosphate; D010732:Phosphofructokinase-1; D011770:Pyruvate Kinase; C029063:fructose-1,6-diphosphate