A polyamine is an organic compound having two or more primary amino groups –NH
2.
Low-molecular-weight linear polyamines perform essential functions in all living cells. Primary examples are putrescine, cadaverine, spermidine, and spermine. In animals, their levels are maintained from both the diet and de novo synthesis, and their decline with age is associated with various pathologies. Polyamine metabolism is regulated by the activity of the enzyme ornithine decarboxylase (ODC). Polyamines are found in high concentrations in the mammalian brain.
This class of compounds also includes several synthetic substances that are important feedstocks for the chemical industry, such as ethylene diamine H
2N–CH
2–CH
2–NH
2, 1,3-diaminopropane H
2N–(CH
2)
3–NH
2, and hexamethylenediamine H
2N–(CH
2)
6–NH
2. Certain polyamines are employed on industrial scales as co-reactants (hardeners) with epoxy resins.