Ligand facts for kids

Myoglobin (blue) with its ligand heme (orange) bound.

A ligand is a biochemical substance. Its function is to bind to a biological molecule, and make the molecule perform a function. Ligand binding alters the shape of the receptor protein. This changes the protein's behaviour.

In a narrower sense, it is a signal triggering molecule, binding to a site on a target protein.

The binding occurs by intermolecular forces, such as ionic bonds, hydrogen bonds and van der Waals forces. The docking (association) is usually reversible (dissociation).

Ligands include substrates, inhibitors, activators, and neurotransmitters. The tendency or strength of binding is called affinity.

Related pages

• Signal transduction
• Cytokine
• Agonist
• Receptor antagonist

Images for kids

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  Cobalt complex HCo(CO)4 with five ligands

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  Cobalt(III) complex containing six ammonia ligands, which are monodentate. The chloride is not a ligand.

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  The N-heterocyclic carbene ligand called IMes is a bulky ligand by virtue of the pair of mesityl groups.