After a ligand bonds to a receptor through intermolecular forces

In summary, after a ligand binds to a receptor through intermolecular forces, it can become unbound through thermal fluctuations. However, in some cases the binding may be strong enough that the ligand never becomes unbound. The fate of the unbound ligand depends on the specific ligand and receptor. It may either continue to bind and release repeatedly, or it may only be released after the ligand-receptor complex is internalized and metabolized. This process can be thought of as a one-body problem, similar to radioactive decay, and can vary depending on the concentration and strength of the binding. Biological half-lives refer to the time it takes for half of a substance to be eliminated from the body, and can apply to
  • #1
After a ligand bonds to a receptor through intermolecular forces, how is it unbound and what happens to it after it is?
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  • #2

The liganding species just goes back into solution.

It's 'unbound' the same way any chemical reaction is reversed, through thermal fluctuations.
If something binds strongly enough, it may never come unbound.

In many scenarios, you'll have a situation where some reaction occurs elsewhere which causes the bound state to rise in energy relative the unbound one.
  • #3

ooh so if it was a drug it would keep attaching to other receptors until it was metabolized?
  • #4

It depends on the receptor and ligand. In some cases, the binding is not strong and easily reversed. The ligand will bind and release over and over, and you'd need a high concentration of ligand to be effective. In other cases, the ligand binds and isn't released until after the ligand-receptor complex is internalized and either split up by an enzymatic reaction that allows the receptor to be recycled, or the whole ligand-receptor complex is metabolized.
  • #5

ooh ok that makes sense tyvm!-
  • #6

A colleague of mine helped me understand binding and unbinding this way:

Binding is a two-body problem- a chemical reaction A + B -> C, with a rate constant that depends on the concentration of both A and B.

Unbinding is a one-body problem, and can be thought of as equivalent to radioactive decay. The rate constant only depends on one object, and the binding rate constant may be different than the unbinding rate constant.
  • #7

ah i see so is that what biological half-lives are? I've heard the term, but i thought they were talking about the radioactive isotopes you ingest before scans

1. What is a ligand?

A ligand is a molecule or ion that binds to a receptor through intermolecular forces, such as hydrogen bonding, van der Waals interactions, or electrostatic interactions.

2. What is a receptor?

A receptor is a protein or other molecule on the surface of a cell that binds to specific ligands, triggering a cellular response. Receptors can be found in various tissues and play important roles in physiological processes.

3. How do intermolecular forces contribute to ligand-receptor binding?

Intermolecular forces, such as hydrogen bonding and van der Waals interactions, play a crucial role in stabilizing the ligand-receptor complex. These forces are attractive interactions between molecules that allow them to bind to each other.

4. What happens after a ligand binds to a receptor?

After a ligand binds to a receptor, a series of events is triggered within the cell, leading to a specific response. This response can include changes in cellular signaling pathways, gene expression, and protein production, among others.

5. Can the strength of ligand-receptor binding be altered?

Yes, the strength of ligand-receptor binding can be altered by various factors, such as the concentration of the ligand and the receptor, the presence of other molecules, and the affinity between the ligand and receptor. This can affect the overall cellular response to the ligand-receptor interaction.

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