In association with the catalytically inactive AdoMetDC prozyme, catalyzes the decarboxylation of S-adenosyl-L-methionine which is essential for the biosynthesis of the polyamine spermidine. Required for growth and survival during the bloodstream life cycle stage (PubMed:18949025). H(+) + S-adenosyl-L-methionine = CO2 + S-adenosyl 3-(methylsulfanyl)propylamine Binds 1 pyruvoyl group covalently per subunit. Allosterically activated by AdoMetDC prozyme. Activated by putrescine and to a lesser extent by spermidine, norspermidine and spermine. Inhibited by 5'-([(Z)-4-amino-2-butenyl]methylamino)-5'-deoxyadenosine (MDL 73811). 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. Expressed during both bloodstream (BF) and procyclic insect (PF) life cycle stages. Is synthesized initially as an inactive proenzyme (PubMed:17485680). 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 produce ammonia and the pyruvoyl group blocking the N-terminus of the alpha chain (By similarity). RNAi-mediated knockdown causes cell growth arrest followed by death. Putrescine levels are increased and the production of spermidine, glutathionyl-spermidine and trypanothione is severely reduced. In addition, expression levels of AdoMetDC prozyme and ornithine carboxylase (ODC) are increased. Belongs to the eukaryotic AdoMetDC family.