A model for the allosteric regulation of pH-sensitive enzymes.
1. In an enzyme that has two independent binding sites for a ligand, any inhibitor that binds solely to the free enzyme will give rise to positive co-operativity. 2. A model is considered for the allosteric control of enzymes by effectors in which their effects are mediated by ligand-induced perturbations of the ionization constants of a group or groups involved in the binding of substrate to the active site. 3. The model described offers a plausible explanation for the observation that the sigmoidal initial-rate curves reported for some regulatory enzymes are not expressed at all pH values where the enzyme is catalytically active.
D000494:Allosteric Regulation; D000495:Allosteric Site; D004791:Enzyme Inhibitors / Q000378:metabolism; D004798:Enzymes / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008024:Ligands; D008954:Models, Biological
D004791:Enzyme Inhibitors; D004798:Enzymes; D008024:Ligands