S-Methylmethionine
| S-methylmethionine[1] | ||
|---|---|---|
 | ||
| IUPAC name (3-Amino-3-carboxy-propyl)-dimethyl-sulfonium | ||
| Other names S-Methyl-L-methionine | ||
| Identifiers | ||
| CAS number | 4727-40-6  | |
| PubChem | 458 | |
| Jmol-3D images | {{#if:C[S+](C)CCC(C(=O)O)N|Image 1 | |
| ||
| Properties | ||
| Molecular formula | C6H15NO2S+ | |
| Molar mass | 164.247 g/mol | |
| Melting point | 139 °C (282 °F)[1] (bromide salt, decomp.) 134 °C (273 °F)[1] (chloride salt, decomp.) | |
| Hazards | ||
| LD50 | 2760 mg/kg (iv, mice, chloride salt)[1] | |
(verify) (what is: / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa) | ||
| Infobox references | ||
S-Methylmethionine (SMM) is a derivative of methionine with the chemical formula (CH3)2S+CH2CH2CH(NH3+)CO2–. This cation is an intermediate in many biosynthetic pathways owing to the sulfonium functional group. The natural derivative S-methylmethionine is biosynthesized from L-methionine which is first converted to S-adenosylmethionine. The subsequent conversion, involving replacement of the adenosyl group by a methyl group is catalyzed by the enzyme methionine S-methyltransferase. S-methylmethionine is particularly abundant in plants, being more abundant than methionine.[2]
Vitamin U is a synonym for S-methylmethionine.[3] The term was coined in 1950 by Garnett Cheney for anti-ulcerogenic[4] factors in raw cabbage juice that speed healing of peptic ulcers. It is claimed to have protective effects in the gastrointestinal mucosa and in the liver.[5]
Biosynthesis and biochemical function
S-Methylmethionine arises via the methylation of methionine by S-adenosyl methionine (SAM). The coproduct is S-adenosyl homocysteine.[2]
The biological roles of S-methylmethionine are not well understood. Speculated roles include methionine storage, use as a methyl donor, regulation of SAM.[2] A few plants use S-methylmethionine as a precursor to the osmolyte dimethylsulfoniopropionate (DMSP). Intermediates include dimethylsulfoniumpropylamine and dimethylsulfoniumpropionaldehyde.[6]
Beer flavor precursor in barley malt
S-Methylmethionine is found in barley and during the malting process, particularly the curing stage in kilning, heat causes it to break down to form dimethyl sulfide (DMS).[7]
References
- ↑ 1.0 1.1 1.2 1.3 Merck Index, 12th ed., 10165 ISBN 0-911910-12-3
- ↑ 2.0 2.1 2.2 Bourgis F (1999). "S-methylmethionine plays a major role in phloem sulfur transport and is synthesized by a novel type of methyltransferase". The Plant Cell Online 11 (8): 1485–1498. doi:10.1105/tpc.11.8.1485.
- ↑ National Center for Biomedical Ontology. "Methylmethionine Sulfonium Chloride".
- ↑ Cheney G (September 1950). "Anti-peptic ulcer dietary factor (vitamin "U") in the treatment of peptic ulcer". J Am Diet Assoc 26 (9): 668–72. PMID 15436263.
- ↑ Patel AD, Prajapati NK (2012). "Review on Biochemical Importance of Vitamin-U". Journal of Chemical and Pharmaceutical Research 4 (1): 209–215.
- ↑ McNeil SD (1999). "Betaines and related osmoprotectants. Targets for metabolic engineering of stress resistance". Plant Physiology 120 (4): 945–949. doi:10.1104/pp.120.4.945.
- ↑ Hornsey IS (1999). Brewing. Royal Society of Chemistry. p. 47. ISBN 9780854045686.
External links
- Vitamin U at the US National Library of Medicine Medical Subject Headings (MeSH)