Allosteric effector is an enzyme activator or inhibitor that has its effect at a site other than the catalytic site of the enzyme. The effector can be described as an agent that facilitates a specific effect or an agent that yields an outcome in response to nerve stimulation.
The presence of an allosteric effector can change the affinity of the enzyme for its substrate, or alter the maximal catalytic activity of the enzyme, or both. Allosteric effectors can bind to regulatory proteins involved in RNA transcription altering its activity. During this process, activator proteins become active in order to bind to the DNA, which promotes RNA polymerase and inactivates repressor proteins. RNA polymerase can then bind to the DNA.