Ligand binding reaction time scales

Therefore two main arrangements are applied. For a slow rate of dissociation related to the CE run-time scale the sample can be preincubated prior to electrophoresis and the reaction set to equilibrium. After equilibrium is obtained, an aliquot of the reaction mixture is analyzed by CE, which is used simply as a method to separate and quantify the analyte, ligand, and complex in the preequilibrated mixture. During the CE run, which is carried out in a buffer without reactants, no equilibrium is established. However, as the rate of dissociation is comparably slow, the reactants and the complex present in the mixture can be separated and their concentrations (which are those of the incubation equilibrium) determined quantitatively. Change of the mutual concentrations of analyte and ligand in the mixture allows conclusion about the binding constant and the stoichiometry of the complex formed. 

These results illustrate the complexity of ligand binding in a simple two-component system. The results further indicate the time resolution of the MHQ technique. The reaction between metmyoglobin and azide is a useful molecular timer, but the kinetic s are not proportional to [N3 ] observation of the intermediate described here can be used to argue that the particular rapid-freezing instrument operates below the 100 ps time scale. 

Once the ligand binds to the receptor, it initiates a series of biochemical reactions that induce a short-term response (e.g., phosphorylation state of an intermediate protein) and/or a longer-term response as a result of a regulated gene response. These networks respond relatively rapidly, exhibiting dynamics with characteristic time scales of seconds to minutes. A cell is often presented with multiple, competing cues, and it processes that infor-... 

---