The
enzymeadenosylmethionine decarboxylase (
EC4.1.1.50) catalyzes the conversion of
S-adenosyl methionine to
S-adenosylmethioninamine.
Polyamines such as
spermidine and
spermine are essential for
cellulargrowth under most conditions, being implicated in many cellular processes including DNA, RNA and
protein synthesis.
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. These
proteins can be divided into two main groups which show little
sequence similarity either to each other, or to other pyruvoyl-dependent amino acid decarboxylases: class I
enzymes found in
bacteria and
archaea, and class II
enzymes found in
eukaryotes. In both groups the active enzyme is generated by the post-translational
autocatalyticcleavage 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.
