Nucleotides polyamine increases

Using an easy and versatile procedure for oligonucleotide-polyamine conjugation [46], polyamines were conjugated to distinct terminal and internal positions along nucleotide sequences. Upon poly amine attachment to terminal nucleosides, the hybridization efficiency with the complementary nucleotide sequence increased with the number of cationic amines. However, tethering to an internal nucleoside resulted in a considerable decrease in duplex stabihty. However, in phosphorothioates... 

A phosphate-modified spermine has also been conjugated to nucleotide sequences, increasing the counter-strand affinity as evidenced by moiutoring the corresponding melting temperatures [62]. Biophysical and in vitro data supported the potentially favorable properties expected for DNA-polyamine conjugates. However, modification of 2 -deoxy-2 -succinylamido-uridine led to substantial decrease in counter-strand affinity when incorporated internally in DNA [62]. 

Fluorescence detection is often used where no other property of the solute (e.g. UV of RI detection) is convenient and can be either an intrinsic property of the solute itself or a derivatised form of the solute. Solution studies have indicated that the sensitivity of detection can be increased by up to three orders of magnitude over UV. This has increased the popularity of post-column fluorescence detection methods for may compounds, including physiological fluids, catecholamines, and other polyamines. A popular use of fluorescence detection is in peptide chemistry where no convenient intrinsic chro-mophore is present. Derivatising agents such as orthophthalaldehyde and fluorescamine are used extensively in both pre- and post-column systems allowing detection of low picomole quantities (Chapter 11). In addition, detection can be performed using the intrinsic fluorescence of many compounds such as steroids, vitamins, and nucleotides. 

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