S-adenosyl methionine decarboxylase (ADOMETDC, SAMDC)

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Function

both proenzyme processing & catalytic activity are stimulated by putrescine
catalytic activity is inhibited by iodoacetic acid
amine & polyamine biosynthesis
S-adenosylmethioninamine biosynthesis
synthesized initially as an inactive proenzyme
formation of the active enzyme involves a self-maturation process in which the active site pyruvoyl group is generated from an internal Ser via an autocatalytic post-translational modification
two non-identical subunits are generated from the proenzyme
the alpha chain is derived from the carboxyl end of the proenzyme
post-translation cleavage follows an unusual pathway, termed non-hydrolytic serinolysis, in which the side chain hydroxyl group of Ser supplies its oxygen atom to form the C-terminus of the beta chain, while the remainder of the Ser undergoes an oxidative deamination to produce NH3 & the pyruvoyl group blocking the N-terminus of the alpha chain

S-adenosyl-L-methionine .      <-->
(5-deoxy-5-adenosyl)(3-aminopropyl)-methylsulfonium salt + CO2

Cofactor: pyruvoyl group