Selenocysteine

**Semantic type:** Amino Acid, Peptide, or Protein

**Definition:** An unusual amino acid of proteins, the selenium analogue of cysteine, in which a selenium atom replaces sulphur. Involved in the catalytic mechanism of seleno enzymes such as formate dehydrogenase of E. coli and mammalian glutathione peroxidase.

**Synonyms:** - 3-Selenyl-L-Alanine - SELENOCYSTEINE - SeC