Nucleic acid derivatives specific

Enhancing the overall resistivity of the body is observed upon treatment with a number of known drugs immunostimulants (caffeine, phenamine, methyluracil), vitamins (retinol, ascorbic acid, vitamins of group B), nucleic acid derivatives, and also drugs of natural or genetically engineered origin made specifically for this purpose. 

Vidarabine is an adenosine nucleoside obtained from cultures of Streptomyces antibloticus (56). Cellular enzymes convert vidarabine to mono-, di-, and triphosphate derivatives that interfere with viral nucleic acid replication, specifically inhibiting the early steps in DNA synthesis. This agent was used originally as an antineoplastic drug. Its antiviral effect is, in some cases, superior to that of idoxuridine or cytarabine. 

Some of the substances that have been separated by this method are given in papers referred to by Morris and Morris (1964) amino acids, peptides (particularly those having molecular weights ranging from 500 to 5000), polypeptide antibiotics, proteins (including enzymes), carbohydrates (although for most compounds in this chemical class other fractionation methods are much more frequently applied), purines, pyrimidines, nucleic acid derivatives, tRNA s that are specific for various amino acids, organic acids, steroids, lipids, antibiotics that are not peptides, porphyrins, pterins, vitamin B,2 and other vitamins, lipoic acid, and alkaloids. The countercurrent-distribution procedure of Holley et al. (1965) is widely used, sometimes with modifications. Korte et al. (1965) have separated three isomers of tetrahydrocannabinol. 

Nucleic acid nu- kle-ik- [fr. their occurrence in cell nuclei] (1892) n. A family of macromolecules, of molecular masses ranging upward from 25,000, found in the chromosomes, nucleoli, mitochondria, and cytoplasm of all cells, and in viruses in complexes with proteins, they are called nu-cleoproteins. On hydrolysis they yield purines, pyrimidines, phosphoric acid, and a pentose, either D-ribose or D-deoxyribose from the last, the nucleic acid derive their more specific names, ribronucleic acid and deoxyribonucleic acid. Nuclear acids are liner (i.e., unbranched) chains of nucleotides in which the 5 -phosphoric group of each one is esterified with the 3 -hydroxyl of the adjoining nucleotide. Black JG (2002) Microbiology, 5th edn. John Wiley and Sons Inc., New York. 

Harber and Maddocks (79) discussed the separation of purine analogs ftom nucleic acid derivatives on ECTEOLA-cellulose TLC specifically describing the isolation of azathioprine, an imidazole derivative of 6-mercaptopurine to which it is converted in vivo, and 6-MP from a mixture of purines and pyrimidines. 

In contrast to Mg + and Mn +, which stabilize secondary structures in DNA and RNA, Cu + destabilizes DNA and RNA double helices, and this is attributed to the ability of copper to bind to the nucleic acid bases. Chao and Kearns have recently explored the possibility that this binding, as detected by electron and nuclear magnetic resonance spectroscopy, might be used to probe certain structural features of nucleic acid molecules, such as the looped out regions of tRNAs. The nature of the Cu complexes formed with nucleosides and nucleotides varies with the specific nucleic acid derivatives used and also the pH. Thus, in the pH range 8.5—10.0, copper forms a water-soluble complex with the ribose OH groups of the ribonu-cleosides and 5 -ribonucleotides, but these complexes cannot form with any of the deoxynucleosides or the 2 - and 3 -ribonucleotides. It is suggested that copper(ii) could stabilize unusual polynucleotide structures or interactions in certain enzymatic systems the latter could, for example, be responsible for translational errors in the RNA,DNA polymerase system which are known to be induced by transition metals. 

Hereafter Lu et al. replaced the cationic functionality at the lower rim by a nucleobase. Hybrids between calixarenes and nucleic acid derived compounds have attained more and more attention and will be presented in Sect. 24.4 in more detail. Equally to the amino and guanidino derivatives the uracil calixarene conjugate was used for the interfacial interaction, now specifically via base paring to the complementary nucleoside adenine in the subphase rather than by electrostatic attraction. The same principle was used for the reverse arrangement An adenine calixarene... 

The synthetic nucleic acid analogs have recently much attention, and numerous studies have been devoted to the preparation and the properties of these analogs, which may find a number of application possibilities as polymeric drugs, photosensitive polymers, and other valuable materials. The present paper concerns the preparation of the HPLC resins containing nucleic acid derivatives which can be applied to HPLC systems using specific interaction between nucleic acid bases. 

In the present paper, chemically and thermally stable nucleic acid derivatives are chemically bonded on silica gel for HPLC systems and specific separations of nucleic acid moieties are reported on. 

N. T., Lhomme J., Helene C. Sequence-specific recognition, photocrosslinking and cleavage of the DNA double helix by an oligo-[alpha]-thymidylate covalently linked to an azidoproflavine derivative. Nucleic Acids Res. 1987 15 7749-7760. 

The unique properties of oligonucleotides create crosslinking options that are far different from any other biological molecule. Nucleic acids are the only major class of macromolecule that can be specifically duplicated in vitro by enzymatic means. The addition of modified nucleoside triphosphates to an existing DNA strand by the action of polymerases or transferases allows addition of spacer arms or detection components at random or discrete sites along the chain. Alternatively, chemical methods that modify nucleotides at selected functional groups can be used to produce spacer arm derivatives or activated intermediates for subsequent coupling to other molecules. 

The formation of an aldehyde group on a macromolecule can produce an extremely useful derivative for subsequent modification or conjugation reactions. In their native state, proteins, peptides, nucleic acids, and oligonucleotides contain no naturally occurring aldehyde residues. There are no aldehydes on amino acid side chains, none introduced by post-translational modifications, and no formyl groups on any of the bases or sugars of DNA and RNA. To create reactive aldehydes at specific locations within these molecules opens the possibility of directing modification reactions toward discrete sites within the macromolecule. 

Weith, H.L., Wiebers, J.L., and Gilham, P.T. (1970) Synthesis of cellulose derivatives containing the dihy-droxyboryl group and a study of their capacity to form specific complexes with sugars and nucleic acid components. Biochemistry 9, 4396-4401. 

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