|Jmol-3D images||Image 1|
|Molar mass||164.247 g/mol|
|Melting point||139 °C (282 °F) (bromide salt, decomp.)
134 °C (273 °F) (chloride salt, decomp.)
|LD50||2760 mg/kg (iv, mice, chloride salt)|
|Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)|
|(what is: / ?)|
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.
Vitamin U is a synonym for S-methylmethionine. The term was coined in 1950 by Garnett Cheney for anti-ulcerogenic 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.
Biosynthesis and biochemical function
The biological roles of S-methylmethionine are not well understood. Speculated roles include methionine storage, use as a methyl donor, regulation of SAM. A few plants use S-methylmethionine as a precursor to the osmolyte dimethylsulfoniopropionate (DMSP). Intermediates include dimethylsulfoniumpropylamine and dimethylsulfoniumpropionaldehyde.
Beer flavor precursor in barley malt
- Merck Index, 12th ed., 10165 ISBN 0-911910-12-3
- 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.