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

Abstract

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.