<biochemistry, chemistry> Of a binding site in a protein, usually an enzyme.

The catalytic function of an enzyme may be modified by interaction with small molecules, not only at the active site, but also at a spatially distinct (allosteric) site of different specificity.

Of a protein, a protein possessing such a site. An allosteric effector is a molecule bound at such a site that increases or decreases the activity of the enzyme.

This entry appears with permission from the Dictionary of Cell and Molecular Biology

(22 Feb 2008)