5
What is binding affinity?
Using the dissociation constant (K
d
) to quantify binding affinity allows researchers to deeply understand molecular
interactions and make informed decisions for follow-up experiments.
Understanding molecular interactions is a common topic in much of
chemical and biological research. For some purposes, it can be enough
to either prove or disprove whether an interaction is happening. But
in order to fully understand an interaction, it is crucial to dig deeper
in order to answer questions like: How strong is the interaction? How
long will it last? What does this mean for its biological function?
To answer these questions, it's essential to quantify the interaction,
and measuring its binding affinity is an important aspect of doing
so. Binding affinity is typically described by a parameter called
dissociation constant (K
d
), which defines the likelihood that an
interaction between two molecules will break. The smaller the
dissociation constant, the less likely the interaction is to break,
meaning the more tightly bound the two molecules are and the
higher the affinity is between them.
Binding affinity is a metric used across both academia and industry.
Academic researchers generally use it to learn about structure-
function relationships or the intermolecular interactions that drive
biological processes. In industry, researchers are often looking for
molecules best suited to a specific purpose, for example a drug
candidate that binds selectively and specifically to a drug target.
Comparing the binding affinities of a library of candidates allows
them to select the candidates that are potentially suited as a drug.
