What is "ionophore"

ionophore \i*on"o*phore`\ n. [ion + -phore] (Biochemistry) A compound that enhances transport of ions across cellular membranes, by binding them and carrying them across. As a class ionophores tend to be lipophilic in nature; each compound is usually specific for one or a small number of ions.

n. (context chemistry English) any substance that can transfer ions from a hydrophilic medium (such as water) to a hydrophobic medium, or across a biological membrane, normally by forming a complex with it; an ion carrier

An ionophore is a chemical species that reversibly binds ions. Many ionophores are lipid-soluble entities that transport ions across a cell membrane. Ionophore means "ion carrier" as these compounds catalyze ion transport across hydrophobic membranes such as liquid polymeric membranes (carrier-based ion selective electrodes) or lipid bilayers found in the living cells or synthetic vesicles ( liposomes)

Some ionophores are synthesized by microorganisms to import ions into their cells. Synthetic ion carriers have also been prepared. Ionophores selective for cations and anions have found many applications in analysis.

The two broad classifications of ionophores synthesized by microorganisms are:

1. Carrier ionophores that bind to a particular ion and shield its charge from the surrounding environment. This makes it easier for the ion to pass through the hydrophobic interior of the lipid membrane. An example of a carrier ionophore is valinomycin, a molecule that transports a single potassium cation. Carrier ionophores may be proteins or other molecules.
2. Channel formers that introduce a hydrophilic pore into the membrane, allowing ions to pass through without coming into contact with the membrane's hydrophobic interior. An example of a channel former is gramicidin A. Channel forming ionophores are usually large proteins.