Positive allosteric modulator

A substance that binds a protein at a site distinct from its main activating site and increases the protein’s response to an activator.

Allosteric regulation: Control of a protein’s activity through a molecule binding at a site distinct from its functional site. Positive modulators are one way allosteric binding increases protein activity.
GABAA receptor positive allosteric modulator: A substance that enhances GABAA receptor responses to gamma-aminobutyric acid. Benzodiazepines are a major drug class acting through this receptor mechanism.
Negative allosteric modulator: A substance that binds allosterically and reduces a protein’s response to an activator. It produces the opposite direction of functional change.
Receptor (biochemistry): A protein that detects a chemical signal and initiates or regulates a cellular response. Many positive allosteric modulators act on receptors that respond to endogenous ligands.
Probe dependence: A variation in an allosteric modulator’s effect depending on which orthosteric ligand is present. A positive effect with one agonist may not hold for another.
Orthosteric site: A protein binding site where an endogenous ligand or substrate produces the defining response. Positive allosteric modulators bind elsewhere, rather than occupying this main functional site.
Benzodiazepine: A class of drugs that enhances GABAA receptor activity through a distinct binding site. These drugs exemplify positive allosteric modulation in clinical use.
Silent allosteric modulator: A ligand that binds an allosteric site without changing the response to an orthosteric ligand. Unlike a positive modulator, it does not enhance the activator’s effect.
Ligand (biochemistry): A molecule that binds selectively to a biological macromolecule. A positive allosteric modulator is defined by its binding and functional effect.
Allosteric cooperativity factor: A quantitative measure of how binding at one site changes ligand binding at another site. It helps separate changes in agonist affinity from other forms of modulation.

Linked from 7 pages