An alkane-alpha,omega-diamine comprising a straight-chain pentane core with amino substitutents at positions 1 and 5. A colourless syrupy liquid diamine with a distinctive unpleasant odour, it is a homologue of putresceine and is formed by the bacterial decarboxylation of lysine that occurs during protein hydrolysis during putrefaction of animal tissue. It is also found in plants such as soyabean.