An enzyme-linked receptor, also known as a catalytic receptor, is a transmembrane receptor, where the binding of an extracellular ligand causes enzymatic activity on the intracellular side.
[1] Hence a catalytic receptor is an integral membrane protein possessing both catalytic, and receptor functions.
[2] They have two important domains, an extra-cellular ligand binding domain and an intracellular domain, which has a catalytic function; and a single transmembrane helix.
The signaling molecule binds to the receptor on the outside of the cell and causes a conformational change on the catalytic function located on the receptor inside the cell.
Examples of the enzymatic activity include: The following is a list of the five major families of catalytic receptors: