“…Amino acids ligands were used in affinity chromatography of proteins (Kanoun et al, 1986;Wu et al, 1992) (Jahreis et al, 2001), oligosaccharides (Delattre et al, 2005) and endotoxins (Wei et al, 2007), however, very recently was asserted for the first time their application for pDNA purification. In these latest works we have described the total removal of E. coli impurities using a histidine-agarose matrix (Sousa et al, 2006) and the baseline separation of sc and oc isoforms either using histidine (Sousa et al, 2005) or arginine as chromatographic ligands (Sousa et al, 2008). The fact that considerably lower salt concentration must be used to isolate sc isoform with arginine-based matrix also revealed an important process advantage (Sousa et al, 2008), suggesting the feasibility of exploiting affinity interactions of amino acids with nucleic acids to develop an interesting bioseparation methodology.…”