amine and polyamine metabolism putrescine metabolism Metabolism of putrescine, 1,4-diaminobutane. Putrescine is one of polyamines that are found in a wide range of organisms from bacteria to plants and animals, especially when these cells are proliferating or under stressful conditions (Tabor & Tabor, 1984). Polyamines can modulate the functions of RNA, DNA, nucleotide triphosphates, proteins, and other acidic substances, and they contribute to stimulate cell growth and viability (Igarashi & Kashiwagi, 2000). Putrescine is the metabolic precursor of spermidine and spermine. GO:0009445 pathway UPa:UPA00457