Choline
- ( 2-hydroxyethyl) - trimethylammonium chloride
- 2-hydroxy- N, N, N- trimethyl- ethanaminiumchlorid
- Biocolina
- Hepacholine
- Lipotril
A05
Colorless, hygroscopic solid with an amine-like odor weak
Fixed
Decomposition at 180 ° C
- Well in water, methanol and ethanol
- Poor in carbon tetrachloride, chloroform, benzene
Attention
Template: Infobox chemical / molecular formula search available
Choline [ coli ː n] (from gr χολή cholé, Galle ') is a primary, monohydric alcohol and a quaternary ammonium compound. Commercially available is usually the choline chloride.
History
Choline was first discovered in 1849 by Adolph Strecker in pig bile and 1862 characterized and named. 1866 and 1867 it was first synthesized chemically, independently of Adolf Baeyer and Charles Adolphe Wurtz.
Occurrence
Choline is very common among living things. In the form of its acetic acid ester, there is the neurotransmitter acetylcholine, in the form of its phosphoric acid ester is part of the lecithins ( phosphatidylcholine ) and also intermediate of the metabolism.
In foods, choline lies both in free form and bound as sphingomyelin or phosphatidylcholine ago ( lecithin). In smaller quantities it is in cereals (eg wheat germ ), soybeans, vegetables and nuts. The highest amounts are found in egg yolks.
Production and representation
Choline may be represented by exhaustive methylation of the amine function of the monoethanolamine. Another synthesis is the reaction of trimethylamine with ethylene oxide.
Use
In supplements, feed, drugs against liver damage ( fatty liver ).
In semiconductor production choline is used as a cleaning agent for wafers.
In biotechnology, choline chloride is used in culture media for plants.
In the form of 18F -choline is used in positron emission tomography tracers in the diagnosis of prostate cancer.
Biological Significance
By the transfer of an acetyl moiety on the choline by choline acetyltransferase ( EC 2.3.1.6 ), the biosynthesis of the important neurotransmitter acetylcholine. Reversal in this reaction, the acetylcholinesterase is responsible for the hydrolysis of this ester to acid and choline.
Choline is phosphorylated by choline kinase, the ( EC 2.7.1.32 ). The resulting zwitterionige O- phosphocholine serves as a starting material in the biosynthesis of phosphatidylcholine, which are an essential component of biomembranes.
Choline to betaine may be further, the zwitterionigen trimethylglycine, oxidized, which is an important methylene group next to an intermediary in the metabolism of folic acid, S-adenosylmethionine, and vitamin B12.
Choline also functions as a lipotropic factor, and can prevent the storage of fat in the liver.
Various esters of choline, such as that known as suxamethonium succinyldicholine, act as agonists of acetylcholine receptors without having to be rapidly degraded by existing cholinesterases can. After a short excitation leads to a long-lasting depolarization and thus to muscle relaxation.
Vitamin -like substance
Was formerly called vitamin choline and has been - as well as the adenine - referred to as vitamin B4, although it was known that the compound can be synthesized by the human body. Given adequate supply of the amino acid methionine, choline can be formed in sufficient quantity in the body. Currently choline is therefore often classified as a vitamin-like substance, which also include the inositol counts. In monogastric animals, it is also absorbed by the food, since choline is present as a component of phosphatidylcholines in the cell membrane. Here ruminants are an exception, because choline is almost completely degraded in the rumen.