Human platelet 6-phosphofructokinase. Relation between inhibition by Mg-ATP2-and cooperativity towards fructose 6-phosphate and investigations on the formation of a ternary complex.
Human platelet 6-phosphofructokinase (EC 2.7.1.11) shows cooperativity towards Fru-6-P and is allosterically inhibited by high Mg-ATP2- concentrations. No relation could be demonstrated between the cooperativity towards Fru-6-P and the inhibition by Mg-ATP2-. Increasing the concentrations of Mg-ATP2- only raised the apparent Km values for Fru-6-P, but did not change the Hill constants. A possible formation of a Mg-ATP2--enzyme-Fru-6-P complex during catalysis was investigated. Our calculations suggest that such a ternary complex is indeed formed during the reaction.
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000494:Allosteric Regulation; D001665:Binding Sites; D001792:Blood Platelets / Q000201:enzymology*; D005636:Fructosephosphates / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D008433:Mathematics; D010732:Phosphofructokinase-1 / Q000097:blood*; D011485:Protein Binding
D005636:Fructosephosphates; D000255:Adenosine Triphosphate; D010732:Phosphofructokinase-1; D008274:Magnesium