Receptor Biochemistry

A receptor is a molecule usually found on the surface of the cell and receiving signals (chemical or hormonal) from outside the cell. Receptors belong to class of proteins. Binding of some substance to the receptor brings about changes that direct the actions of cell containing receptor. Ligand is the molecule that binds to the receptor and it can be a peptide, a hormone, neurotransmitter, drug or a toxin etc. Each receptor possesses two functional domains: recognition domain that binds the ligand such as hormone, and a coupling domain involved in signal transduction. Signal transduction includes the events within the cell that occur in response to a signal following binding of a ligand to receptor.

Cell-surface receptors are also known as trans-membrane receptors as they are located on outer surface of the plasma membrane to bind the ligand outside the cell. Cell surface receptors are membrane-anchored integral proteins that mediate the communication between the outside world and the …show more content…
to pass through the membrane. Ion channels are pore-forming proteins also referred to as cell-membrane bound receptors. They are mostly found on synaptic structures and are involved in neuronal activities. Ions pass down their electrochemical gradient through ion channels without the requirement of ATP or metabolic energy. Ion channels are an important component of the nervous system as activation of these channels by neurotransmitters mediate conduction across nerve synapses. Ion channels also play a vital role in exerting cellular response to toxins and venoms. Various biological processes involving prompt changes in cells such as contraction of cardiac, skeletal, and smooth muscles, activation of T-cells and release of hormones are also mediated through ion