Probably in association with catalytically inactive AdoMetDC prozyme, catalyzes the decarboxylation of S-adenosyl-L-methionine which is essential for the biosynthesis of the polyamine spermidine (PubMed:9677309, PubMed:10413038). Required for growth and survival during the bloodstream life cycle stage (By similarity). H(+) + S-adenosyl-L-methionine = CO2 + S-adenosyl 3-(methylsulfanyl)propylamine Binds 1 pyruvoyl group covalently per subunit. Allosterically activated by AdoMetDC prozyme (By similarity). Activated by putrescine (PubMed:9677309, PubMed:10413038). Inhibited by spermine and methylglyoxal-bis(guanylhydrazone) (MGBG) and slightly by spermidine (PubMed:9677309). Inhibited by 5'-([(Z)-4-amino-2-butenyl]methylamino)-5'-deoxyadenosine (MDL 73811) (PubMed:10413038). Amine and polyamine biosynthesis; S-adenosylmethioninamine biosynthesis; S-adenosylmethioninamine from S-adenosyl-L-methionine: step 1/1. Forms a heterodimer with catalytically inactive AdoMetDC prozyme; heterodimerization is required to activate AdoMetDC. Is synthesized initially as an inactive proenzyme (PubMed:9677309, PubMed:10413038). Formation of the active enzyme involves a self-maturation process in which the active site pyruvoyl group is generated from an internal serine residue via an autocatalytic post-translational modification (By similarity). Two non-identical subunits are generated from the proenzyme in this reaction, and the pyruvate is formed at the N-terminus of the alpha chain, which is derived from the carboxyl end of the proenzyme (By similarity). The post-translation cleavage follows an unusual pathway, termed non-hydrolytic serinolysis, in which the side chain hydroxyl group of the serine supplies its oxygen atom to form the C-terminus of the beta chain, while the remainder of the serine residue undergoes an oxidative deamination to the alpha chain (By similarity). Belongs to the eukaryotic AdoMetDC family.