In biochemistry, a binding site is a region on a protein, DNA, or RNA to which specific other molecules and ions—in this context collectively called ligands—form a chemical bond.
Binding sites also exist on antibodies as specifically coded regions that bind antigens based upon their structure.
The term saturation refers to the fraction of total binding sites that are occupied at any given time. When more than one type of ligand can bind to a binding site, competition ensues.
An equilibrium exists between unbound ligands and bound ligands.
Binding sites also exhibit chemical specificity, a measure of the types of ligands that will bond, and affinity, which is a measure of the strength of the chemical bond.
Binding sites are often an important component of the functional characterization of biomolecules. For example, the characterization the binding site of a substrate to an enzyme is essential to model the reaction mechanism responsible for the chemical change from substrate to product.
A more specific type of binding site is the transcription factor binding site, present on DNA.
Famous quotes containing the words binding and/or site:
“What is lawful is not binding only on some and not binding on others. Lawfulness extends everywhere, through the wide-ruling air and the boundless light of the sky.”
—Empedocles 484–424 B.C., Greek philosopher. The Presocratics, p. 142, ed. Philip Wheelwright, The Bobbs-Merrill Co., Inc. (1960)
“That is a pathetic inquiry among travelers and geographers after the site of ancient Troy. It is not near where they think it is. When a thing is decayed and gone, how indistinct must be the place it occupied!”
—Henry David Thoreau (1817–1862)