Noun
English Wikipedia has an article on:homoserineWikipedia
homoserine (countable and uncountable, plural homoserines)
(biochemistry) The amino acid 2-amino-4-hydroxybutanoic acid that is an intermediate in the biosynthesis of methionine, threonine and isoleucine
Homoserine is the branching point with the threonine pathway, where instead it is isomerised after activating the termainal hydroxyl with phosphate (also used for methionine biosynthesis in plants). Source: Internet