Nucleic acids mild acid hydrolysis

Mild hydrolysis of nucleic acids yields the monomeric nucleotides. Subsequent complete hydrolysis of a nucleotide furnishes three structural subunits ... 

ADENOSINE. [CAS 58-61-7]. An important nucleoside composed of adenine and ribose. White, crystalline, odorless powder, mild, saline, or bitter taste, Mp 229C, quite soluble in hot water, practically insoluble in alcohol. Formed by isolation following hydrolysis of yeast nucleic acid. The upper portion of Structure 1 represents the adenine moiety, and the lower portion of the pentose, D-ribose. 

Notice was early made of the fact that true nucleic acid, as such or after mild hydrolysis, shows all the reactions that are exhibited by amorphous (t.e., not pure) D-glucal.21... 

Very mild acid, or dilute acid at or below room temperature, has little effect on nucleic acids. Indeed, dilute acids (e.g., trichloroacetic, HCIO4, HC1) at 0 to 25°C are routinely used to precipitate (isolate) nucleic acids and other polar macromolecules. Somewhat stronger acidic conditions (prolonged exposure to dilute acid or dilute acid at increased temperature or acid strength) cause depurination, i.e., acid-catalyzed hydrolysis of purine N-glycosides. Thus, 15 min of treatment with 1 N HC1 at 100°C removes most of the purines from DNA and RNA. Much harsher acidic conditions (several hours at 100°C or more concentrated acid) are required to remove pyrimidine N-glycosides. Some limited... 

As a result of Levene s painstaking researches it was definitely established, after years of controversy, that mild hydrolysis of ribosenucleic acid gives directly the four mononucleotides. The tetranucleo-tide structure has since been substantiated by comparison of the heats of combustion of the separate components of nucleic acid with that of nucleic acid itself. Levene therefore suggested that the fundamental molecule of ribosenucleic acid is a tetranucleotide, in which there are... 

In the early attempts to identify the nitrogenous bases of desoxy-ribosenucleic acid, some confusion arose for two reasons. At first, the products obtained by hydrolysis of nucleoprotein were studied, and there was no assurance that any particular base came from the nucleic acid rather than from the protein. Then, when the nucleic acid itself became available, the hydrolytic agents at first employed were sufficiently drastic to cause some deamination of the amino-purines (with the production of some xanthine and hypoxanthine) and some demethylation of thymine to uracil. In 1874, Piccard isolated guanine (and h3T>oxanthine) from sperm nuclein. Kossel and Neumann discovered in the hydrolysate of thymus nucleic acid two new pyrimidine bases which they named thy-mine and cytosine but they assigned incorrect empirical formulas to them. In 1894, they correctly described thymine as CsHgOjNs, but cytosine was not purified and characterized till much later. " " Levene now analyzed a series of nucleic acids from a variety of sources and found " that they all contained guanine and adenine. By mild hydrolysis of thymus nucleic acid, Steudel obtained guanine and adenine as the sole purine bases and demonstrated that they occur in equi-molecular proportions. Levene and Mandel confirmed this result and showed that the two purine bases and the two pyrimidine bases (thymine and cytosine) all occur in thymus nucleic acid in equimolecular proportions. 

The slow, post-irradiation decrease in viscosity ( after-effect ) was investigated by Daniels, Scholes, Weiss, and Wheeler, who relate this phenomenon to the labilization of phosphate bonds by the intermediate formation of labile phosphate esters. Leading to this conclusion is the observation that about fifteen times as much inorganic phosphate can be obtained by acid hydrolysis of irradiated, aqueous solutions of nucleic acid as is formed directly by the radiation. It is, therefore, thought that, after the labile phosphate esters have been formed, they undergo slow acid hydrolysis, and that this mild hydrolysis occurring at the diester phosphate groups, even... 

Properties White, crystalline, odorless powder mild, saline, or bitter taste. Mp 229C. Quite soluble in hot water practically insoluble in alcohol. Derivation Isolation following hydrolysis of yeast nucleic acid. 

Both 5-hydroxyuracil (isobarbituric acid, I) and 5-hydroxyuridine (II) can be prepared from the corresponding 5-bromopyrimidines by mild basic hydrolysis [5-8]. 5-Hydroxyuracil inhibits enzymatic degradation of uracil [9] and is one of three pyrimidine analogues (the other two are 5-bromouracil and 6-azauracil) that inhibit the rate of incorporation of uracil into nucleic... 

The laboratory synthesis of oligonucleotides and polynucleotide fragments is a subject of great importance. Much has already been acheived (Chapter 10.4C). In addition to hydrolysis, however, the nucleic acids are very sensitive to a wide range of chemical reactions, for example, the heterocyclic bases are subject to alkylation, oxidation and reduction. Generally only mild reactions can be used in the construction of an oligonucleotide chain... 

Preparation. The preparation of 2-deoxy-D-erythro-pentose by hydrolysis of the natural deoxypentosenucleic acids is tedious and the yields are low. The nucleic acids first are hydrolyzed enzymatically to deoxyribonucleo-sides (V-deoxyribofuranosyl purines and pyrimidines). Further mild acidic hydrolysis then liberates the sugar from the purine bases 57). The sugar-pyrimidine linkage, however, is more stable and its hydrolysis by stronger acid is accompanied by destruction of the deoxypentose to levulinic acid. Direct mercaptanolysis of deoxyribosenucleic acids has been employed to obtain the dibenzyl mercaptal of the deoxysugar 58). 

Caton-Williams et al7 reported a one-pot synthesis of nucleoside 5 -(a-P-thio) triphosphates (89) and phosphorothioate nucleic acids without protecting any nucleoside functionalities. The chemistry of this faeile synthesis involves the treatment of unprotected nucleosides with a mild phosphitylating reagent (salicyl phosphorochloridite and pyrophosphate) followed by sulfurization and hydrolysis to afford the corresponding analogues. These compounds can be easily purified by ion-exchange chromatography. 

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