The polyamines, putrescine [NH2(CH2)4NH2], spermidine

NH(CH2)3NH2], are organic polycations present in all eukary-otes and are essential for cell proliferation (Tabor and Tabor, 1984; Igarashi and Kashiwagi, 2010; Pegg and Casero, 2011). Since their primary and secondary amino groups are protonat-ed at physiological pH, these polyamines interact electrostati-cally with negatively charged molecules such as DNA, RNA, proteins and phospholipids (Bachrach, 2005) and they have been proposed to regulate cellular activities at transcriptional, translational and post-translational levels. The polyamines dif-fer from inorganic cations like Mg2+ or Ca2+ in that their positive charges are spaced at defined distances by flexible methy-lene chains that can participate in hydrophobic interactions. Polyamines, putrescine, spermidine and spermine, are ubiquitous in living cells and are essential for eukaryotic cell growth. These polycations interact with negatively charged molecules such as DNA, RNA, acidic proteins and phospholipids and modulate vari-ous cellular functions including macromolecular synthesis. Dysregulation of the polyamine pathway leads to pathological condi