Allosteric site binding among proteins results in numerous interactions, not only between those proteins, but also with others not physically connected. These interactions may affect protein functioning and may be affected by allosteric regulation.
Allostery is the process by which biological macromolecules (mostly proteins) transmit the effect of binding at one site to another, often distal, functional site, allowing for regulation of activity. ~ American molecular biophysicist Hesam Motlagh et al
Allostery functions as a dynamic interrelated network, creating ensemble behavior in affected proteins. Allostery effectively entangles proteins into a regulated web, behaving like the protein equivalent of quantum nonlocality.
The biomechanics of allostery are only partly understood; but allostery works via conformational changes in the proteins involved, and thermodynamics within the effective domain of the allosteric network.
Drugs often function via allostery. Further, allostery provides for adaptive evolution outside any changes in genetic code.