Stimulation of Trypanosoma brucei pyruvate kinase by fructose 2,6-bisphosphate.
The activity of pyruvate kinase present in a crude extract of the bloodstream form of Trypanosoma brucei was greatly increased by fructose 2,6-bisphosphate, which converted the saturation curve for phosphoenolpyruvate from a sigmoid into a hyperbola with no change in V. Phosphate and arsenate had an effect opposite to that of fructose 2,6-bisphosphate and the apparent Ka for fructose 2,6-bisphosphate was shifted from 75 nM to 1.5 microM by the presence of 5 mM phosphate. Fructose 1,6-bisphosphate had effects similar to those of fructose 2,6-bisphosphate but at approximately 4000-fold higher concentrations. Pyruvate kinases of Crithidia luciliae and of Leishmania major, two trypanosomatids which are like T. brucei in containing glycosomes, were also stimulated by fructose 2,6-bisphosphate and inhibited by phosphate.
D000818:Animals; D004789:Enzyme Activation / Q000187:drug effects; D005635:Fructosediphosphates / Q000494:pharmacology*; D006019:Glycolysis; D006598:Hexosediphosphates / Q000494:pharmacology*; D008297:Male; D010710:Phosphates / Q000494:pharmacology; D010728:Phosphoenolpyruvate / Q000494:pharmacology; D011770:Pyruvate Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D014346:Trypanosoma brucei brucei / Q000201:enzymology*
D005635:Fructosediphosphates; D006598:Hexosediphosphates; D010710:Phosphates; D010728:Phosphoenolpyruvate; C027652:fructose 2,6-diphosphate; D011770:Pyruvate Kinase