The enzyme methionine decarboxylase () catalyzes the chemical reaction
This enzyme belongs to the family of lyases, specifically the carboxy-lyases, which cleave carbon-carbon bonds. The systematic name of this enzyme class is L-methionine carboxy-lyase (3-methylthiopropyl amine-forming). Other names in common use include L-methionine decarboxylase and L-methionine carboxy-lyase.