Catalyzes the production of spermidine from putrescine and decarboxylated S-adenosylmethionine (dcSAM). Has a strong preference for putrescine as substrate, and has very low activity towards 1,3-diaminopropane. Has extremely low activity towards spermidine.
[1]"Molecular cloning of a cDNA encoding human spermine synthase." Korhonen V.-P., Halmekytoe M., Kauppinen L., Myoehaenen S., Wahlfors J., Keinaenen T., Hyvoenen T., Alhonen L., Eloranta T., Jaenne J. DNA Cell Biol. 14:841-847(1995) [2]"Sequence analy