In biochemistry, the binding of a ligand to a macromolecule is often enhanced if there are already other ligands present on the same macromolecule (this is known as cooperative binding). The Hill coefficient provides a way to quantify this effect.
It describes the fraction of the macromolecule saturated by ligand as a function of the ligand concentration
|θ||Fraction of the ligand-binding sites on the receptor protein which are occupied by the ligand. (dimensionless)|
|KA||Ligand concentration occupying half of the binding sites ( the microscopic dissociation constant) (dimensionless)|
|L||Free (unbound) ligand concentration (dimensionless)|
|n||Hill coefficient, depending on the context in which the Hill equation is being used (dimensionless)|