S-Methylmethionine
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| Names | |
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| IUPAC name
(3-Amino-3-carboxy-propyl)-dimethyl-sulfonium
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| Other names
S-Methyl-L-methionine
Vitamin U |
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| Identifiers | |
4727-40-6  |
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| ChEBI | CHEBI:17728  |
| ChemSpider | 128519 |
| Jmol 3D model | Interactive image |
| KEGG | C03172 |
| PubChem | 145692 |
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| Properties | |
| C6H15NO2S+ | |
| Molar mass | 164.247 g/mol |
| Melting point | 139 °C (282 °F; 412 K)[1] (bromide salt, decomposes) 134 °C (273 °F)[1] (chloride salt, decomposes) |
| Vapor pressure | {{{value}}} |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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 verify (what is ?) |
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| 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]
S-Methylmethionine is sometimes referred to as vitamin U,[3] but it is not considered a true vitamin. The term was coined in 1950 by Garnett Cheney for uncharacterized anti-ulcerogenic[4] factors in raw cabbage juice that may help speed healing of peptic ulcers.
S-Methylmethionine is claimed to have protective effects in the gastrointestinal mucosa and in the liver.[5]
Contents
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 Merck Index, 12th ed., 10165 ISBN 0-911910-12-3
- ↑ 2.0 2.1 2.2 Lua error in package.lua at line 80: module 'strict' not found.
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External links
- Vitamin U at the US National Library of Medicine Medical Subject Headings (MeSH)
