Further, it is a transmembrane receptor, an enzyme catalyst, an enzyme-coupled receptors known as catalytic receptor binding of extracellular ligands, enzymatic activity of the catalyst side.Hence receptors in cells, the receptor I make is an integral membrane protein having both functions. They have two key areas of the transmembrane helix and the intracellular domain comprising the extracellular ligand binding domain, a catalytic function. Binds to cell signaling molecule, causing a conformational change of the function of the catalyst located inside the cell receptor.