Multiple binding partners

Without exception, proteins carry out their functions in living organisms via direct interactions with themselves or through interactions with other proteins or biomolecules. The processes are likely to involve multiple binding partners in multiple binding steps, and may or may not take place across membrane barriers between cells or cell organelles. Because these processes involve complex biological pathways, they and the phenotypes they produce are rarely understood in detail. 

Wittchen, E. S. Haskins, J. et al. (1999). "Protein interactions at the tight jimction. Actin has multiple binding partners, and ZO-1 forms independent complexes with ZO-2 and ZO-3." JBiol Chem, 274(49), 35179-85. 

Strength with different binding partners and across multiple studies. Unfortunately, AG° and AG° vary with the temperature and the nature of the solvent, making comparisons of studies performed under highly dissimilar conditions somewhat dubious. Although most studies can be carried out under standard conditions, one can easily envision cases where the addition of salt or variation of pH, temperature, or other conditions is unavoidable (e.g., due to protein denaturation). 

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