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-methylthiopropanamine-forming). Other names in common use include L-methionine decarboxylase, and L-methionine carboxy-lyase.
Hagion H; Nakayama K (1968). "Amino acid metabolism in microorganisms. Part IV. L-Methionine decarboxylase produced by Streptomyces strain". Agric. Biol. Chem. 32: 727–733. doi:10.1080/00021369.1968.10859127.