Inhibition of fructose-1,6-bisphosphatase from pig liver by fructose-6-phosphate.
The inhibition of the neutral form of fructose-1,6-bisphosphatase from pig liver by fructose-6-phosphate was investigated in the substrate concentration range of 0.05-500 microM by determination of the rate of formation of labelled inorganic phosphate from [1-32P]fructose-1,6-bisphosphate. The inhibition of the enzyme by fructose-6-phosphate is biphasic, the extent of inhibition decreases with increasing substrate concentrations. Even at high concentrations of fructose-6-phosphate the enzyme is not inhibited completely. The results were interpreted in terms of the model of MONOD, WYMAN and CHANGEUX [10] by assuming a weak competition of fructose-6-phosphate and fructose-1,6-bisphosphate at the catalytic site and a cooperation of the two ligands at the same allosteric site.
D000818:Animals; D006597:Fructose-Bisphosphatase / Q000037:antagonists & inhibitors*; D005636:Fructosephosphates / Q000494:pharmacology*; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D013552:Swine
D005636:Fructosephosphates; C027618:fructose-6-phosphate; D006597:Fructose-Bisphosphatase