The enzyme adenosylmethionine decarboxylase (EC 4.1.1.50) catalyzes the conversion of S-adenosyl methionine to S-adenosylmethioninamine.
S-adenosylmethionine decarboxylase (AdoMetDC) plays an essential regulatory role in the polyamine biosynthetic pathway by generating the n-propylamine residue required for the synthesis of spermidine and spermine from putrescein.
[1][2] Unlike many amino acid decarboxylases AdoMetDC uses a covalently bound pyruvate residue as a cofactor rather than the more common pyridoxal 5'-phosphate.
In both groups the active enzyme is generated by the post-translational autocatalytic cleavage of a precursor protein.
This cleavage generates the pyruvate precursor from an internal serine residue and results in the formation of two non-identical subunits termed alpha and beta which form the active enzyme.