Final answer:
Enzyme-coupled receptors are cell-surface receptors with intracellular domains that are associated with an enzyme. Ligand binding to the extracellular domain of an enzyme-coupled receptor activates the associated enzyme, resulting in a cellular response. One example of an enzyme-coupled receptor is the tyrosine kinase receptor.
Step-by-step explanation:
Enzyme-coupled receptors, also known as enzyme-linked receptors, are cell-surface receptors with intracellular domains that are associated with an enzyme. These receptors have large extracellular and intracellular domains, but the membrane-spanning region consists of a single alpha-helical region of the peptide strand. When a ligand binds to the extracellular domain of an enzyme-coupled receptor, a signal is transferred through the membrane, activating the associated enzyme. This activation sets off a chain of events within the cell that eventually leads to a response.
One example of an enzyme-coupled receptor is the tyrosine kinase receptor. It is an enzyme-coupled receptor that transfers phosphate groups to tyrosine molecules. Ligands bind to the extracellular domain of two nearby tyrosine kinase receptors, causing the receptors to bond together and leading to the addition of phosphates to tyrosine residues on the intracellular domain. These phosphorylated residues then transmit the signal to the next messenger within the cytoplasm.