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S-adenosyl-L-methionine

S-Adenosyl methionine
S-Adenosyl-L-methionin.svg
S-adenosylmethionine spacefill.png
S-adenosylmethionine.png
Names
IUPAC name
(2S)-2-Amino-4-[[(2S,3S,4R,5R)-5-(6-aminopurin-9-yl)-3,4-dihydroxyoxolan-2-yl]methyl-methylsulfonio]butanoate
Other names
S-Adenosyl-L-methionine; SAM-e; SAMe, AdoMet, ademethionine
Identifiers
29908-03-0 YesY
3D model (Jmol) Interactive image
ChEMBL ChEMBL1088977 N
ChemSpider 8041295 YesY
ECHA InfoCard 100.045.391
KEGG C00019 N
MeSH S-Adenosylmethionine
PubChem 9865604
Properties
C15H22N6O5S
Molar mass 398.44 g·mol−1
Pharmacology
A16AA02 (WHO)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YesYN ?)
Infobox references

S-Adenosyl methionine is a common cosubstrate involved in methyl group transfers, transsulfuration, and aminopropylation. Although these anabolic reactions occur throughout the body, most SAM-e is produced and consumed in the liver. More than 40 methyl transfers from SAM-e are known, to various substrates such as nucleic acids, proteins, lipids and secondary metabolites. It is made from adenosine triphosphate (ATP) and methionine by methionine adenosyltransferase (EC 2.5.1.6). SAM was first discovered by Giulio Cantoni in 1952.

In bacteria, SAM-e is bound by the SAM riboswitch, which regulates genes involved in methionine or cysteine biosynthesis.

The reactions that produce, consume, and regenerate SAM-e are called the SAM-e cycle. In the first step of this cycle, the SAM-dependent methylases (EC 2.1.1) that use SAM-e as a substrate produce S-adenosyl homocysteine as a product. This is hydrolysed to homocysteine and adenosine by S-adenosylhomocysteine hydrolase EC 3.3.1.1 and the homocysteine recycled back to methionine through transfer of a methyl group from 5-methyltetrahydrofolate, by one of the two classes of methionine synthases (i.e. cobalamin-dependent (EC 2.1.1.13) or cobalamin-independent (EC 2.1.1.14)). This methionine can then be converted back to SAM-e, completing the cycle. In the rate-limiting step of the SAM cycle, MTHFR (methylenetetrahydrofolate reductase) irreversibly reduces 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate.


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Wikipedia

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