title: [The mechanism of rat liver fructose-1,6-bisphosphate inhibition by fructose-2,6-bisphosphate].
abstract: It was found that a decrease in the activating cation (Mg2+) concentration below [A]0.5 causes the disappearance of cooperativity of the fructose 1.6-bisphosphatase substrate binding sites induced by high fructose 2.6-bisphosphate concentrations without any significant alteration in the extent of the enzyme inhibition. Under these conditions, a competitive type of inhibition (with respect to the substrate) is transformed into a non-competitive type with an increase in the fructose 2.6-bisphosphate concentration. The data obtained confirm the viewpoint that fructose 2.6-bisphosphate binds to the enzyme at two distinct sites, a catalytic and an allosteric ones, differing in their affinity for the inhibitor. It is supposed that the interaction between the allosteric fructose 2.6-bisphosphate binding site and the activator site occupied by Mg2+ is necessary for the cooperative response of the enzyme to the substrate.
authors.forename: N F
authors.initials: NF
authors.lastname: Beliaeva
authors.forename: I R
authors.initials: IR
authors.lastname: Nikulin
authors.forename: F
authors.initials: F
authors.lastname: Korovkin
mesh_terms: D000495:Allosteric Site; D000818:Animals; D006597:Fructose-Bisphosphatase / Q000037:antagonists & inhibitors*; D008099:Liver / Q000201:enzymology*; D008274:Magnesium / Q000378:metabolism; D025481:Phosphofructokinase-2; D010744:Phosphoric Monoester Hydrolases / Q000494:pharmacology*; D051381:Rats; D013379:Substrate Specificity
chemical_list: D025481:Phosphofructokinase-2; D006597:Fructose-Bisphosphatase; D010744:Phosphoric Monoester Hydrolases; D008274:Magnesium
vernacular_title: O mekhanizme ingibirovaniia fruktozo-1,6-bisfosfatazy iz pecheni krysy fruktozo-2,6-bisfosfatom.