Cytidine-5 guanosine-3

Clindamycin (93 R = H), an antibiotic obtained by chlorinating linco-mycin, is converted by a species of Streptomyces into inactive phosphorus-containing compounds. These have been shown to be nucleoside 5 -phosphates derived from adenosine, cytidine, guanosine, and uridine. 

HA was found to be mutagenic in bacteria, and it was reported that plant chromosomes break in the presence of HA, but it was found to be noncarcinogenic to mice. However, Gross did cite some A-hydroxy compounds (i.e. HA derivatives) as carcinogens . The mechanism of mutagenesis of HA was found to involve primarily interaction with the pyrimidine bases of the cytidine-guanosine pairs. 

Zalitis and Feingold357 were able to observe a trace of activity with the 5 -(a-i> glucopyranosyl pyrophosphates) of cytidine, guanosine, and adenosine in reaction with the liver dehydrogenase. The products have not been identified. 

Figure 1 Heterocycles as DNA antimetabolites a cytidine-guanosine base-pair from DNA is shown together with three heterocyclic antimetabolites, 8-azaguanine (90), 6-thioguanine (91) and cytosine arabinoside (92), making clear their similarity to the parent compounds...

Nucleosides (adenosine, cytidine, guanosine,thymidine and uridine) CEC Hypersil Cl8, 3 pm Acetonitrile-5 mM acetic acid, 2-3 mMtriethylamine, pH 5.0 buffer (8 92) 250 mm x 100 pm i.d. effective column length not specified, 20-26°C... 

Nucleosides (adenosine, cytidine, guanosine, uridine, thymidine)... 

RNA A single-stranded copy of DNA consisting of adenosine, cytidine, guanosine, and uridine. Most commonly found as messenger RNA (mRNA), transfer RNA (tRNA), or ribosomal RNA (rRNA). 

To prevent possible nucleotide degradation when using TCA, Khym (K12) suggested the use of amine/Freon solution to back-extract excessive acid. Khym s procedure has been modified by Van Haverbeke and Brown (V3), and has been applied by others to the study of nucleotides (C3, R3, V3) and nucleosides (HIO). Similar to the results reported by Chen et al. (C3), Riss and co-workers (R3) reported that the recovery of the adenosine-, cytidine-, guanosine-, and uridine-5 -nucleotides range from 81 to 99%, with an average recovery of 91% (Table IV). 

The perchloric acid extraction procedure described by Kraus and Rein-both (K27) involves a perchloric acid extraction followed by neutralization with a potassium hydroxide solution. Riss et al. (R3) reported recoveries ranging from 68 to 87% for the adenosine-, cytidine-, guanosine-, and uridlne-5 -nucleotides, with a mean recovery of 78%. Other investigators have used the PCA extraction procedure in the analysis of nucleotides... 

Nucleosides (e. g. adenosine, cytidine, guanosine, pyrimidine, thymidine, uridine) consist of a nitrogenous purine or pyrimidine base linked to a 5-carbon sugar (ribose or deoxyribose). Nucleotides (adenine, cytosine, guanine, thymine, uracil), the phosphate esters of nucleotides, form the basis of RNA and DNA. As infectious viral nucleic acids, they are capable of penetrating the cells and using available enzyme systems for replication. 

To fully check the selectivity of the two hit compounds, all the nucleosides (adenosine, uridine, cytidine, guanosine) and nucleotides (XNP, where X = A, U, C, G, and N = Mono, Di, Tri) were tested systematically. High selectivity of both G49 and G32 only to GTP was clearly exhibited without any obvious cross response to any of other nucleotides or nucleosides (Fig. 17.18). As we observed,... 

Involved in energy transfer in biochemical reactions. Uridine, cytidine, guanosine and thymine triphosphates are also common in biological systems. Nicotinamide adenine dinucleotide phosphate is also an important energy carrier. 

Regulatory control of bacterial thymidylate synthetases by nucleotides has not been reported however, Lorenson et al. (7) investigated that of the chick embryo thymidylate synthetase and found that the 5 -mono-, di-, and triphosphates of adenosine, cytidine, guanosine, and uridine, and of their deoxyribosides, did not inhibit activity. Thus, the activity of the synthetase, from this source at least, does not seem to be subject to allosteric regulation by nucleotides. With crude extracts of Ehrlich ascites... 

AMP, CMP, GMP, IMP, TMP 5 -monophosphates of adenosine, cytidine, guanosine, inosine and thymidine and the prefix d indicates the 2 deoxyribonucleotide. 4MUP and 3NP monophosphate esters of 4-methylumbelliferone and g-naphthol. 

Obtain the following nucleotide standards (Sigma) adenosine-5-monophosphate uridine-5-monophosphate cytidine-5-monophosphate guanosine-5-monophos-phate. Also, obtain the following nucleoside standards (Sigma) adenosine uridine cytidine guanosine. Prepare individual standards at a concentration of 3 0,g/ Xl. 

Molar extinction coefficients for all pH values were calculated from h3Tpochromicities at 260 mpt upon alkaline hydrolysis using the following values of E25Q x 10 (pH 7) 15.4, 7.3, 11.6, and 9.9, for 2 (3 )-monophosphates of adenosine, cytidine, guanosine, and uridine, respectively. All absorbance measurements were made at 20°C. The values in the Note column, when given, are ain absorbance ratios relative to... 

Torres, T. et al. Photophysical characterization of a cytidine-guanosine tethered phthalocyanine-fuller-ene dyad. Chem. Commun. 3, 292-294, 2007. 

The enzyme purified from bull semen dephosphorylates the 5 -phosphate esters of adenosine, uridine, cytidine, guanosine, nicotinamide riboside, and the 5 -phosphate esters of deoxynucleosides, but is inactive with adenosine pyrophosphates and substrates which bear other substituents on the ribose, e.g., adenosine 2, 5 -diphosphate (124). However 5 -nucleo-tidase from potato can hydrolyze the 5 -phosphate of this diphosphate... 

In this experiment students analyze an artificial RNA digest consisting of cytidine, uridine, thymidine, guanosine, and adenosine using a Cjg column and a mobile phase of 0.4% v/v triethylammonium acetate, 5% v/v methanol, and 94.6% v/v water. The chromatogram is recorded using a UV detector at a wavelength of 254 nm. 

FIGURE 11.11 The common ribonucleosides—cytidine, uridine, adenosine, and guanosine. Also, inosine drawn in anti conformation. 

By analogy with the conversion of uridine 1 into cytidines 6, the conventional amination of inosine 235a, guanosine 235b, or xanthosine 235c and their 2 -deoxy analogues to the adenosines 237 requires ... 

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