International Scientific Vocabulary, from methyl + thion- + 2-ine
First Known Use: 1928
Medical Definition of METHIONINE
: a crystalline sulfur-containing essential amino acid C5H11NO2S that occurs in the L-form as a constituent of many proteins (as casein and egg albumin), that is important especially as a source of sulfur for the biosynthesis of cysteine and as a source of methyl groups for transmethylation reactions (as in the biosynthesis of choline, creatine, and adrenaline), and that is used as a dietary supplement for human beings and their domestic mammals and poultry and in the treatment of fatty infiltration of the liver—abbreviation Met
Sulfur-containing essential amino acid, present in many common proteins, particularly egg albumin. It is used in pharmaceuticals, in enriched foods, and as a nutritional supplement and feed additive.