Ribonucleic acid preparation

That the cytoplasmic nucleic acid is present in the mitochondria, the micro-eomes, and the non-sedimentable cell-sap is also known.117 The nuclear ribonucleic acid has been reported to be associated with the nucleolus and the chromosomes.118 It is known, moreover, that the ribonucleic acids of the different parts of the cell are biochemically distinct, since they become labeled with P32 at different rates.119 In liver cells, the nuclear ribonucleic acid is also chemically distinct from the cytoplasmic material, since the two differ in composition.120 It is clear, therefore, that ribonucleic acids prepared from whole cells are likely to be mixtures of various molecular species. 

Askonas, B. A., Rhodes, J. M. Immunogenicity of antigen-containing ribonucleic acid preparations from macrophages. Nature (Lond.) 205, 470-474 (1965). 

Ludwig, E. H., Smull, C. E. Infectivity of histone-poliovirus ribonucleic acid preparations. J. Bact. 85, 1334 (1963)-... 

As has been emphasized previously, whereas some early measurements indicated a molecular weight of the order of 1000 for the ribonucleic acid of yeast, it is now known that the molecule is considerably larger than this. To give accurate values for the molecular weights of ribonucleic acids is however, difficult, since not only do the estimates vary with the method of preparation, but also with the technique used for making the measure-... 

Barker and coworkers have applied gel chromatography in studies of pneumococcal polysaccharides.121 Purification of the type-specific polysaccharide of Pneumococcus Type II was effected by chromatography on Sephadex G-200 in M sodium chloride in this way, the ribonucleic acid, a persistent impurity in preparations of this polysaccharide, was almost completely removed. The complex formed between the polysaccharide and the nucleic acid is largely dissociated in M sodium chloride, so that the two are free in this solvent and may be separated on the basis of their differing molecular size. 

Like most trace elements, nickel can activate various enzymes in vitro, but no enzyme has been shown to require nickel, specifically, to be activated. Howevei, mease has been shown to be a nickel metalloenzyme and has been found to contain 6 to 8 atoms of nickel per mole of enzyme (Fishbein et al.. 1976). RNA (ribonucleic add) preparations from diverse sources consistently contain nickel in concentrations many times higher than those found in native materials from which the RNA ts isolated (Wacker-Vallee, 1959 Sunderman, 1965). Nickel may serve to stabilize the ordered structure of RNA. Nickel may have a role in maintaining ribosomal structure (Tal, 1968, 1969). These studies and other information have led to the suggestion that nickel may play a role in nucleic acid and/or protein metabolism. 

Phosphorolysis of ribonucleic acid with polynucleotide phosphorylase gives a mixture of the diphosphates of the four common nucleosides, which are transformed into triphosphates with enolpyruvate phosphate and pyruvate kinase. This mixture may be used as such as a source of uridine triphosphate in the preparation of the nucleotide-sugar uridine 5 -(a-D-glucopy-ranosyl diphosphate) ( uridine-diphosphate-glucose, UDP-Glc), or as a... 

The discovery of a small proportion of a nucleoside containing thymine42 in the ribonucleic acid of two strains of Escherichia coli, in Aerobacter aero-genes, and in commercial, yeast-ribonucleic acid emphasizes the point made previously,26-28 namely, that the nucleic acids may contain constituents other than those heretofore identified. Alkaline hydrolysis of the ribonucleic acid from E. coli gave nucleotides42 (probably the 2- and 3-phosphate esters) which were converted to the nucleoside with prostatic phospho-monoesterase.62 Enzymic hydrolysis of the nucleic acid preparation also led to the nucleoside, which was degraded further to thymine by hydrolysis with perchloric acid.42 There can be little doubt that this carbohydrate derivative of thymine is intimately bound as part of the polynucleotide chain of this particular ribonucleic acid. 

The aminoacyl transfer reaction, one of the latter stages in protein synthesis, involves incorporation of amino acids from soluble ribonucleic acid-amino acid into ribosomal protein. This reaction requires guanosine triphosphate and a soluble portion of the cell. Evidence has been obtained with rat liver preparations that aminoacyl transfer is catalyzed by two protein factors, aminoacyl transferases (or polymerases) I and n, which have been resolved and partially purified from the soluble fraction. Transferase n activity has also been obtained from deoxycholate-soluble extracts of microsomes. With purified transferases I and n, incorporation is observed with relatively low levels of GTP its sulfhy-dryl requirement is met by a variety of compounds. The characteristics of this purified amino acid incorporating system, in terms of dependency on the concentration of its components, are described. 

BSA was effective for the derivatization of purine and pyrimidine bases [456] and nucleosides [457]. Bases were silylated by heating at 150°C with BSA—acetonitrile (1 3) for 45 min. It was stated that under these conditions the TMS derivative of guanine can be prepared reproducibly, but both cytosine and 5-methylcytosine provided two peaks. Silylation of nucleosides, including pseudouridine, was carried out by heating at 120°C with a 100-fold excess of BSA for 2 h. With the use of OV-17 as the stationary phase, this procedure was adopted for the determination of the composition of ribonucleic acids. 

Two major metabolites were isolated by paper chromatography (from trichloroacetic acid extracts of the cells) and were identified as 8-azaguano-sine 5-phosphate and 8-azaguanosine, respectively. The two compounds were present in the ratio of 4 1. The structure of the 8-azaguanosine 5-phosphate was indicated by chromatographic and electrophoretic comparison of it with (a) the 5-nucleotide prepared by the action of snake venom on the bacterial ribonucleic acid containing 8-azaguanine, and (b) the 3-nucleotide prepared by alkaline hydrolysis. 

As shown in Sec. I, uracils have represented, for more than 90 years, a class of compounds that continually attract organic chemists, biochemists, medicinal chemists, and photobiologists. Uracils were first detected as constituents of ribonucleic acids, from which they were prepared by hydrolysis. Nucleosides derived from uracil are called uridine, pseudouridine, and uridine phosphate, respectively. Recently, uracil moieties were detected in the antibiotic Tunicamycin (85JA7761). 

Derivation By extraction from tea by synthesis from uric acid prepared from yeast ribonucleic acid. 

L21. Loring, H. S., Carpenter, F. H., and Roll, P. M., The hydrolysis of yeast ribonucleic acid by ribonucleinase. I. The extent of hydrolysis and the preparation of ribonudeinase-resistant fractions after ribonucleinase treatment. J. Biol. Chem. 169, 601-608 (1947). 

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