S-Methylmethionine

S-Methylmethionine

Names
IUPAC name (3-Amino-3-carboxy-propyl)-dimethyl-sulfonium
Other names S-Methyl-L-methionine Vitamin U
Identifiers
CAS Number	4727-40-6 Y
3D model (JSmol)	Interactive image
PubChem CID	458
CompTox Dashboard (EPA)	DTXSID00859813
SMILES C[S+](C)CCC(C(=O)O)N
Properties
Chemical formula	C6H15NO2S+
Molar mass	164.247 g/mol
Melting point	139 °C (282 °F) (bromide salt, decomp.) 134 °C (273 °F) (chloride salt, decomp.)
Hazards
Lethal dose or concentration (LD, LC):
LD50 (median dose)	2760 mg/kg (iv, mice, chloride salt)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

S-Methylmethionine is a derivative of methionine with the chemical formula [(CH₃)₃S(CH₂)₂CHNH₃CO₂]⁺. 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.

Biochemical function

The osmolyte dimethylsulfoniopropionate (DMSP), produced by marine algae, is biosynthesized from S-methylmethionine. Intermediates include dimethylsulfoniumpropylamine and dimethylsulfoniumpropionaldehyde.

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).