The presence of a negative allosteric effector on an allosteric protein would: a. cause a shift to the left in the sigmoidal cur
ve. b. increase the number of R conformations. c. decrease the cooperativity of the substrate. d. raise the apparent value of the equilibrium constant, L. e. increase the likelihood of the binding of S.
d. raise the apparent value of the equilibrium constant, L.
Explanation:
Allosteric regulation is a type of regulation of an enzyme by binding an effector molecule at a site other than the protein's active site (i.e., the allosteric site). The equilibrium constant (L) refers to the transition between two forms of an allosteric protein in absence of a ligand. The properties of allosteric enzymes are explained by conformational changes associated with a low-affinity tense (T) state, or a high-affinity relaxed (R) state. Negative allosteric effectors are molecules that bind to the allosteric site on an enzyme in order to decrease its activity, thereby leading the enzyme to a low activity T state and thus increasing the value of the equilibrium constant.
