A non-protein amino acid and a derivative of methionine, homomethionine is synthesized through the process of chain elongation. In Arabidopsis thaliana and other members of the Cruciferae (Brassicaceae) family, it is synthesized as part of a multi-step pathway to generate glucosinolates. Glucosinolates are likely employed as a defense mechanism and are believed to be responsible for the pungent odour and taste associated with this plant family. The process starts in the cytosol of the plant cell with l-methionine as the primary substrate before moving into the chloroplast as 2-oxo-4-methylthiobutanoic acid. In the chloroplast, 3-isopropylmalate dehydratase plays a noteworthy role in catalyzing multiple reactions in the final synthesis of L-homomethionine.

L-Homomethionine Biosynthesis References