Record Information
Creation date2015-10-09 22:32:32 UTC
Update date2017-01-19 02:36:35 UTC
FoodComEx IDPC000758
FoodDB RecordFDB012156
Chemical Information
DescriptionFound in onion, cabbage, coco de mono (Lecythis elliptica), Brazil nuts (Bertholletia excelsa), wheat grains and other plants. Dietary supplement for avoidance of Se deficiency in humans and ruminants It has been suggested that selenomethionine, which is an organic form of selenium, is easier for the human body to absorb than selenite, which is an inorganic form. It was determined in a clinical trial that selenomethionine is absorbed 19% better than selenite.; Selenomethionine is an amino acid containing selenium that cannot be synthesized by higher animals, but can be obtained from plant material. Selenomethionine is the major seleno-compound in cereal grains (wheat grain, maize and rice), soybeans and enriched yeast. Seleno-compounds present in plants may have a profound effect upon the health of animals and human subjects. It is now known that the total Se content cannot be used as an indication of its efficacy, but knowledge of individual selenocompounds is necessary to fully assess the significance. Thus, speciation of the seleno-compounds has moved to the forefront. Since animals and man are dependent upon plants for their nutritional requirements, this makes the types of seleno-compounds in plants even more critical. Se enters the food chain through incorporation into plant proteins, mostly as selenocysteine and selenomethionine at normal Se levels. There are two possible pathways for the catabolism of selenomethionine. One is the transsulfuration pathway via selenocystathionine to produce selenocysteine, which in turn is degraded to H2Se by the enzyme b-lyase. The other pathway is the transamination-decarboxylation pathway. It was estimated that 90% of methionine is metabolized through this pathway and thus could be also the major route for selenomethionine catabolism. (PMID: 14748935, Br J Nutr. 2004 Jan;91(1):11-28.); Selenomethionine is an amino acid containing selenium. The L-isomer of selenomethionine, known as Se-met and Sem, is a common natural food source of selenium. In vivo, selenomethionine is randomly incorporated instead of methionine and is readily oxidized. Its antioxidant activity arises from its ability to deplete reactive species. Selenium and sulfur are chalcogen elements that share many chemical properties and the substitution of methionine to selenomethionine may have no effect on protein structure and function. However, the incorporation of selenomethionine into tissue proteins and keratin in horses causes alkali disease. Alkali disease is characterized by emaciation, loss of hair, deformation and shedding of hooves, loss of vitality and erosion of the joints of long bones.
CAS Number3211-76-5
(2S)-2-amino-4-(methylseleno)Butanoic acidHMDB
(S)-2-amino-4-(methylseleno)-Butanoic acidHMDB
(S)-2-amino-4-(methylseleno)Butanoic acidHMDB
(S)-2-amino-4-(methylseleno)Butyric acidHMDB
2-amino-4-(methylseleno)Butanoic acidHMDB
2-amino-4-(Methylselenyl)butyric acidHMDB
L-2-amino-4-(Methylselenyl)-butyric acidHMDB
Selenium methionineChEBI
Selenomethionine se 75HMDB
Selenomethionine; L-formdb_source
Chemical FormulaC5H11NO2Se
IUPAC name2-amino-4-(methylselanyl)butanoic acid
InChI IdentifierInChI=1S/C5H11NO2Se/c1-9-3-2-4(6)5(7)8/h4H,2-3,6H2,1H3,(H,7,8)
Isomeric SMILESC[Se]CCC(N)C(O)=O
Average Molecular Weight196.11
Monoisotopic Molecular Weight196.995500429
Chemical Taxonomy
Description Belongs to the class of organic compounds known as alpha amino acids. These are amino acids in which the amino group is attached to the carbon atom immediately adjacent to the carboxylate group (alpha carbon).
KingdomOrganic compounds
Super ClassOrganic acids and derivatives
ClassCarboxylic acids and derivatives
Sub ClassAmino acids, peptides, and analogues
Direct ParentAlpha amino acids
Alternative Parents
  • Alpha-amino acid
  • Fatty acid
  • Amino acid
  • Carboxylic acid
  • Monocarboxylic acid or derivatives
  • Selenoether
  • Organic nitrogen compound
  • Hydrocarbon derivative
  • Organic oxide
  • Primary amine
  • Organoselenium compound
  • Organooxygen compound
  • Organonitrogen compound
  • Organopnictogen compound
  • Primary aliphatic amine
  • Organic oxygen compound
  • Carbonyl group
  • Amine
  • Aliphatic acyclic compound
Molecular FrameworkAliphatic acyclic compounds
External Descriptors
Physico-Chemical Properties - Experimental
Experimental logPNot Available
Experimental Water SolubilityNot Available
Melting Point275 oC
Foods of Origin
FoodContent Range AverageReference
Production Data
Production Methodcommercial
Production Method ReferenceNot Available
Production Method Reference FileNot Available
Quantity AvailableProduction upon request, up to 50 mg
Delivery TimeNot Available
Storage Formsolid
Storage Conditions-80°C
StabilityNot Available
PurityNot Available
Spectral Data Upon RequestNot Available
Provider Information
Contact NameContact InstitutionContact Email
Rosa Vazquez
Commercial Vendors
Not Available