Homocysteine




Homocysteine /ˌhoʊmoʊˈsɪstiːn/ is a non-protein α-amino acid. It is a homologue of the amino acid cysteine, differing by an additional methylene bridge (-CH2-). It is biosynthesized from methionine by the removal of its terminal C methyl group. Homocysteine can be recycled into methionine or converted into cysteine with the aid of certain B-vitamins.