<unk>  and its derivatives have many functions in humans and in other organisms. The most notable function is that<unk>  serves as a synthetic precursor for other essential cell components and signalling molecules, such as phospholipids that form cell membranes, the neurotransmitter acetylcholine, and the osmoregulator trimethylglycine (betaine). Trimethylglycine in turn serves as a source of methyl groups by participating in the biosynthesis of S-adenosylmethionine. Phospholipid precursor<unk>  is transformed to different phospholipids, like phosphatidylcholines and sphingomyelins. These are found in all cell membranes and the membranes of most cell organelles. Phosphatidylcholines are structurally important part of the cell membranes. In humans 40–50% of their phospholipids are phosphatidylcholines.<unk>  phospholipids also form lipid rafts in the cell membranes along with<unk> olesterol. The rafts are centers, for example for receptors and receptor signal transduction enzymes. Phosphatidylcholines are needed for the synthesis of VLDLs: 70–95% of their phospholipids are phosphatidylcholines in humans.<unk>  is also needed for the synthesis of pulmonary surfactant, which is a mixture consisting mostly of phosphatidylcholines. The surfactant is responsible for lung elasticity, that is for lung tissue's ability to contract and expand. For example, deficiency of phosphatidylcholines in the lung tissues has been linked to acute respiratory distress syndrome. Phosphatidylcholines are excreted into bile and work together with bile acid salts as surfactants in it, thus helping with the intestinal absorption of lipids. Acetylcholine synthesis<unk>  is needed to produce acetylcholine. This is a neurotransmitter which plays a necessary role in muscle contraction, memory and neural development, for example. Nonetheless, there is little acetylcholine in the human body relative to other forms of<unk> . Neurons also store<unk>  in the form of phospholipids to their cell membranes for the production of acetylcholine. Source of trimethylglycine In humans,<unk>  is oxidized irreversibly in liver mitochondria to glycine betaine aldehyde by<unk>  oxidases. This is oxidized by mitochondrial or cytosolic betaine-aldehyde dehydrogenases to trimethylglycine. Trimethylglycine is a necessary osmoregulator. It also works as a substrate for the BHMT-enzyme, which methylates homocysteine to methionine. This is a S-adenosylmethionine (SAM) precursor. SAM is a common reagent in biological methylation reactions. For example, it methylates guanidines of DNA and certain lysines of histones. Thus it is part of gene expression and epigenetic regulation.<unk>  deficiency thus leads to elevated homocysteine levels and decreased SAM levels in blood.
Choline
Phenylacetic acid
Arachidonic acid
Keto acid
Gluten
Butyric acid
Palate
Inositol