Temperature-induced inversion of allosteric phenomena. Academic Article uri icon

abstract

  • Two instances, involving the enzymes carbamoyl-phosphate synthetase from Escherichia coli and phosphofructokinase from Bacillus stearothermophilus, respectively, are described in which increasing temperature alone causes the actions of an allosteric ligand to change from inhibition to activation. In neither case are these effects due to a change in the activation energy of the enzyme catalyzed reaction induced by the allosteric ligand. Rather, they are due to temperature-dependent changes in the extent to which the binding of allosteric ligand modifies the affinity of the enzyme for substrate. The data can be readily explained by an analysis of the apparent delta H and delta S components of the coupling free energy, which quantitatively describe the actions of allosteric ligands that act in this manner. These observations underscore the shortcomings of expecting to explain the actions of an allosteric ligand solely by the structural perturbations that accompany the binding of an allosteric ligand such as those often revealed by x-ray crystallography.

published proceedings

  • J Biol Chem

altmetric score

  • 3

author list (cited authors)

  • Braxton, B. L., Tlapak-Simmons, V. L., & Reinhart, G. D

citation count

  • 34

complete list of authors

  • Braxton, BL||Tlapak-Simmons, VL||Reinhart, GD

publication date

  • January 1994