ABSTRACT
Spermine phosphate was the rst known naturally occurring polyamine observed in 1678 by Antonie van Leeuwenhoek. More than two centuries had to elapse before the structure of polyamines was determined (reviewed by Bachrach 2010). Afterward, the simpler diamine, putrescine, was discovered in dead animals in decomposition, from here came the origin of its name and the general feeling that this and its sister compounds were only molecules without any biological importance and mere products of the decay of the organic matter. Today, the structures of the most common polyamines present in living organisms: putrescine, spermidine, and spermine, are known as presented in Figure 2.1. They are molecules with two or more amino groups presenting positive charge at physiological pH. Natural polyamines have been well characterized, although as indicated in Chapter 1, they were considered of little importance for a long time, and their interest lagged behind that of other biologically important molecules, such as amino acids, sugars, and nucleotides. It was not until more recently that an ample number of physiological processes in which they are involved have been discovered.
