Allosteric Inhibition

∞ generated and posted on 2016.12.05 ∞

Negative control of enzyme function that involves binding of a substance to a location on the enzyme other than the active site.

Allosteric Inhibition is inhibition that is caused by the binding of an inhibitor to an enzyme somewhere other than to the active site.

The action of the inhibitor substance, after binding to an enzyme, is propagated through the enzyme to the active site, which is then reversibly inactivated in some manner such as through subtle changes in shape. As allosteric inhibition is a kind of non-competitive inhibition, contrast therefore with competitive inhibition.

Figure legend: Note the attachment of the inhibitor molecule at a site other than the active site along with the propagation of the inhibitory signal through the enzyme to the active site. The result is a typically reversible modification of the active site in such a manner that the active site is no longer catalytically active.

Activators of enzyme function also exist, involving substances that also bind other than to the active site, but in this case with that binding is propagated to the active site in such a way that the active site becomes functional for catalysis (or more functional) from a default state in which it is not (or less) functional.