In: Chemistry
In all ligand titrations, the concentration of ligand is varied around the KD of the complex. In a stoichiometric titration, what is the concentration of receptor in relationship to KD? How does this differ from a binding titration experiment? Can you get a KD from a stoichiometric binding Titration? Why do the stoichiometric titration experiment this way, and what kind of information does it give you?
The KD of the complex is known as the equillibrium dissociation constant.The concentration of the unbound ligand at which the binding site is 50%.The smaller the dissociation constant, the more tightly bound the ligand is or we can say higher the affinity between ligand and protein.
The molecules with one binding site, the concentration of the complex [AB]= [A]0[B]/KD+[B] where A0 = Kd[AB]/[B]+[AB].For a simple bimolecular reaction, total bound A molecule to the Bfree is a hyperbola:
Fractional saturation of A=(Bfree)/[Kd+(Bfree)]
yes we can get a Kd from a stoichiometric binding titration,when one fix the stoichiometric binding site.The importance of binding is to measure interactions between two molecules, such as a protein binding another protein, a micromolecule or a nucleic acid. The reactions must be at equillibrium at the time of measurement,and the concentration of one reactant must be varied.