<P> 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 . Hence a catalytic receptor is an integral membrane protein possessing both enzymatic catalytic and receptor functions . </P> <P> They have two important domains, an extra-cellular ligand binding domain and an intracellular domain, which has a Catalytic function; and a 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 . </P> <P> Examples of the enzymatic activity include: </P>

Where are the catalytic domains of receptor enzymes located