Partition function and equilibria in solution

A demonstration is given of the relationship between equil. concns. of species MAi, Bjerrum formation function, ‾n, and grand canonical partition function. The total std. free energy change corresponding to the global satn. process of a receptor, is broken into steps of successive complexation, each corresponding to a change of chem. potential. From the differences between the av. chem. potential at step i and the chem. potential of the first complexation step, the av. cooperativity effect is obtained. The latter proves to be a linear function (i-1), thus showing the existence of a cooperativity function. It is possible to derive the partition function as dependent on site affinity consts. and on cooperativity coeffs.