Valency is defined as the total number of interacting epitopes (identical or otherwise) in a proteins, where each epitope is capable of binding to a specific set of substrates. Valency is a measure of the binding promiscuity of the protein, where increasing valency increases the set of partners a protein can interact with. Multivalency is an important attribute in phase separating proteins, particular scaffolds.
Kiessling et al., (2003). Multivalency in Biological Systems ↩︎