2-Deoxyribose 5-phosphate, acid

Noteworthy is the labelling of so-called peptide nucleic acids (PNAs). These constitute a class of synthetic macromolecules where the deoxyribose phosphate backbone of DNA is replaced by the pseudo-peptide A/-(2-aminoethyl)glycyl backbone, while retaining the nucleobases of DNA [270,271]. PNAs have been labelled at a terminal cysteine-site using A/-(4-[ F]fluorobenzyl)-2-bromoaceta-mide [272-274], a reagent belonging to another class of thiol-selective reagents. 

DNA contains the bases adenine A), thymine (T), guanine (G), and cytosine (C). These bases are covalently attached to the deoxyribose phosphate to form nucleotides. The respective nucleotides are called dcoxyadenylic add (dA), deoxythy-midylic add (dT), deoxyguanylic acid (dC), and deoxycj tidylic acid (dC). The prefix "deoxy" indicates that the sugar is deoxyribose, rather than ribo e. The word "acid" indicates that the ribose con tains a covalently bound phosphoric acid group. 

Nucleic acid A biopolymer consisting of repeating units of ribose or deoxyribose, phosphate, and selected bases. 

The aspect of a reversible reaction of fluorinase was of major importance for further optimizations and by addition of the enzyme L-amino acid oxidase (L-AAO) the oxidative removal of formed L-methionine was enabled. In this way, the equilibrium of the reaction was pulled toward 5 -[ F]FDA and allowed very high radiochemical yields of 95% within 1-2 h. Accordingly, the F-labeled compounds 5 -[ F]fluoro-5 -deoxyinosine (5 -[ F]FDI) (O Fig. 42.30h), 5 -[ F]fluoro-5 -deoxyribose phosphate (O Fig. 42.30c)y and 5 -[ F]fluoro-5 -deoxyribose (O Fig. 42.30d) were successfully produced from 5 -[ F]fluoro-5 -deoxyadenosine (Deng et al. 2006, Onega et al 2009, 2010). In the base-swap strategy, the 5 [i F]fluoro-5 -deoxyribose phosphate O Fig. 42.30c) could be further transformed into... 

Fig. N-9. The spiral structure of deoxyribonucleic acid, or DNA— the basic building block of life on earth. It s a double helix (a double spiral structure), with the sugar (deoxyribose)-phosphate (phosphoric acid) backbone represented by the two spiral ribbons. Connecting the backbone are four nitrogenous bases (a base is the nonacid part of a salt) adenine (A) paired with thymine (T), and guanine (G) paired with cytosine (Q with the parallel spiral ribbons held together by hydrogen bonding between these base pairs. Adenine and guanine are purines, while thymine and cytosine are pyrimidines.

Some more active phosphates in any living organism are ATP (adenosine triphosphate), RNA (ribose nucleic acid), and DNA (deoxyribose nucleic acid). Where orthophosphate in DNA and RNA can be considered functionally structural, as a sugar bridge in DNA and RNA, such is not the case for the tripolyphosphate moiety in adenosine triphosphate. To demonstrate adequately the activity of adenosine triphosphate it is necessary to consider the structural formula of this molecule (Figure 2.1). 

A polyamide nucleic acid chimeric molecule has been computer modeled by Nielsen et al. by replacing the deoxyribose phosphate backbone of DNA through an achiral polyamide backbone (39). The new backbone, supposed to be homomorphous to DNA, consists of aminoethylgylcine units, which can be regarded as reduced diglycine. Since the nucleobase is connected to the backbone via nitrogen, the... 

Two successful attempts have been reported to replace the entire deoxyribose phosphate backbone on one side and still preserve the features of the DNA structure especially in view of antisense and antigene potential on the other side [85,86,87,88,89,90], One is the morpholino derivative and the other one the peptide nucleic acids (PNA) which contains an N-(2-aminoethyl) glycine-based pseudopeptide backbone (Figure 8) [71], It is obvious from the way PNA can mimic DNA that the deoxyribose backbone is not essential for the function of a helical duplex structure. 

Cytosine was isolated from hydrolysis of calf thymus in 1894 and by 1903 its structure was known and it had been synthesized from 2-ethylthiopyrimidin-4(3H)-one. The acid hydrolysis of ribonucleic acid gives nucleotides, among which are two cytidylic acids, 2 -and 3 -phosphates of cytidine further hydrolysis gives cytidine itself, i.e. the 1-/3-D-ribofuranoside of cytosine, and thence cytosine. The deoxyribonucleic acids likewise yield deoxyribonucleotides, including cytosine deoxyribose-5 -phosphate, from which the phosphate may be removed to give cytosine deoxyriboside and thence cytosine. 

RNA is relatively resistant to the effects of dilute acid, but gentle treatment of DNA with 1 mM HCl leads to hydrolysis of purine glycosidic bonds and the loss of purine bases from the DNA. The glycosidic bonds between pyrimidine bases and 2 -deoxyribose are not affected, and, in this case, the polynucleotide s sugar-phosphate backbone remains intact. The purine-free polynucleotide product is called apurinic acid. 

The nucleic acids DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are biological polymers that act as chemical carriers of an organism s genetic information. Enzyme-catalyzed hydrolysis of nucleic acids yields nucleotides, the monomer units from which RNA and DNA are constructed. Further enzyme-catalyzed hydrolysis of the nucleotides yields nucleosides plus phosphate. Nucleosides, in turn, consist of a purine or pyrimidine base linked to Cl of an aldopentose sugar—ribose in RNA and 2-deoxyribose in DNA. The nucleotides are joined by phosphate links between the 5 phosphate of one nucleotide and the 3 hydroxyl on the sugar of another nucleotide. 

Three classes of nucleic acid triple helices have been described for oligonucleotides containing only natural units. They differ according to the base sequences and the relative orientation of the phosphate-deoxyribose backbone of the third strand. All the three classes involve Hoogsteen or reverse Hoogsteen-like hydrogen bonding interaction between the triple helix form-... 

The actual building blocks for the nucleic acids are the nucleotides, which are formed in an esterification reaction between nucleosides and phosphate three OH functions of ribose, and two of deoxyribose, can undergo esterification ... 

Three types of monomers found in DNA, a nucleic acid, are the phosphate group, the deoxyribose group and a base. These are illustrated by... 

In 1977, Kellogg and Fridovich [28] showed that superoxide produced by the XO-acetaldehyde system initiated the oxidation of liposomes and hemolysis of erythrocytes. Lipid peroxidation was inhibited by SOD and catalase but not the hydroxyl radical scavenger mannitol. Gutteridge et al. [29] showed that the superoxide-generating system (aldehyde-XO) oxidized lipid micelles and decomposed deoxyribose. Superoxide and iron ions are apparently involved in the NADPH-dependent lipid peroxidation in human placental mitochondria [30], Ohyashiki and Nunomura [31] have found that the ferric ion-dependent lipid peroxidation of phospholipid liposomes was enhanced under acidic conditions (from pH 7.4 to 5.5). This reaction was inhibited by SOD, catalase, and hydroxyl radical scavengers. Ohyashiki and Nunomura suggested that superoxide, hydrogen peroxide, and hydroxyl radicals participate in the initiation of liposome oxidation. It has also been shown [32] that SOD inhibited the chain oxidation of methyl linoleate (but not methyl oleate) in phosphate buffer. 

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