Temperature-induced inversion of allosteric phenomena
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...
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Published in | The Journal of biological chemistry Vol. 269; no. 1; pp. 47 - 50 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Bethesda, MD
American Society for Biochemistry and Molecular Biology
07.01.1994
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Subjects | |
Online Access | Get full text |
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Summary: | 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. |
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Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2 |
ISSN: | 0021-9258 1083-351X |
DOI: | 10.1016/s0021-9258(17)42309-x |