Stochastic linkage: Effect of random fluctuations on a two-state process

When the two-state process A⇄B is asymmetrically perturbed by random fluctuations, a unidirectional shift of the equilibrium between the two states is observed. Random fluctuations destabilize the state that is populated nondeterministically by the fluctuating rate. This effect of random fluctuations on the preexisting equilibrium between the two states is analogous to the allosteric regulation of conformational transitions in biological macromolecules induced by ligand binding to one of the two states. The unidirectional effect of random fluctuations of the two-state process A⇄B can be interpreted as a stochastic linkage that couples noise to conformational transitions.