Ultra-weak reversible protein-protein interactions

Free solution technologies mostly fail when addressed to such systems. The AUC has the highest practical capability, but evaluation of the data to yield Ka values is complicated by the presence of thermodynamic/hydrodynamic effects of a comparable order of magnitude. These effects can however be computationally removed by means of suitable algorithms, and Kd values of up to 50 mM can be characterised. The relative merits of velocity and equilibrium approaches are discussed, and both are shown to have particular advantages.