Choline
Choline is a metabolic precursor of the important neurotransmitter, acetylcholine (Reaction 1 below)

CDP is also linked to a phosphorylated form of choline to form CDP-choline in the predominant mechanism of phosphatidylcholine synthesis (Figure 19.5). Oxidation of choline to glycine betaine is one mechanism of donating a methyl group in biosynthesis of methionine (see here).

Sphingomyelin is made by transferring choline from phosphatidylcholine to a ceramide (Figure 19.13).

Other reactions involving choline:

> 1. Choline + Acetyl-CoA <=> Acetylcholine + CoASH (catalyzed by Choline Acetyltransferase)

> 2. Acetylcholine + H 2O <=> Choline + Acetate (catalyzed by Acetylcholinesterase)

> 3. Choline + ATP <=> Phosphocholine + ADP (catalyzed by Choline Kinase)

See also: Neurotransmission, Acetylcholine, Phosphatidylcholine