Desoxyribosenucleic acid

Acylation, tritylation and, III, 90 of polyuronides, I, 334 Adenine, from desoxyribosenucleic acid, I, 237... 

An earlier distinction made between plant nucleic acid and animal nucleic acid has been abandoned with the definite identification of a ribosenucleic acid occurring concomitantly with desoxyribosenucleic acid in certain animal tissues (e.g., in pancreas and in chicken embryos ),... 

It seems probable that, as with desoxyribosenucleic acid, the size of the particles of ribosenucleic acid depends upon the treatment to which the acid has been subjected, the size being smaller when less mild methods of isolation are applied. Bawden and Pirie had pointed out that the size of the tobacco mosaic virus ribosenucleic acid particles is larger than that of the particles of yeast ribosenucleic acid as usually prepared. Loring has now found that purified, commercial yeast ribosenucleic acid solutions have about the same specific viscosity as have solutions of the alkali-treated ribosenucleic acid of tobacco mosaic virus hence, their molecular sizes are probably of the same order (about 15,000). 

Finally, there seems good reason to believe that, in native ribosenucleic acid, there are labile linkages of a nature as yet unknown electrophoretic studies by Cohen show that both ribosenucleic acid and desoxyribosenucleic acid may possess either four or five acidic groups per tetranucleotide unit, depending upon the previous treatment. It would be of interest to ascertain if the material endowed with a secondary phosphoric dissociation is a simple tetranucleotide, and if this is the material which can be completely dephosphorylated by a mixture of monoesterase and diesterase. 

Sources from which desoxyribosenucleic acid has been isolated include fish sperm, thymus, spleen, pancreas, testicles, placenta, mammary glands, brain, liver, kidney, blood cells, thyroid, intestines, lungs, lymphatic glands, bacteria, and tumor tissue. It is difficult to obtain a uniform product, free from protein the first serviceable method was that of Neumann, which has been improved upon by later workers. The nucleic acid from thym,us glands may be isolated in the following manner ... 

Desoxyribosenucleic acid is readily hydrolyzed by mineral acids but is more resistant to alkaline fission than is ribosenucleic acid. Owing to the nature of the constituent sugar, the purine nucleotides are even more unstable than those of ribosenucleic acid. Hence, by acid hydrolysis of thymus nucleic acid, only the two pyrimidine nucleotides" " can be isolated. 

All chemical methods of hydrolyzing desoxyribosenucleic acid, with-... 

The hydrolysis of desoxyribosenucleic acid to the constituent nucleosides was achieved by Levene and London in 1929, by the action of the enzymes of intestinal juice. They passed a solution of the acid through a segment of the gastro-intestinal tract of a dog, and collected it from an intestinal fistula. The solution was then covered with a layer of toluene and incubated in a thermostat during four to seven days, small portions of gastro-intestinal secretion being added daily. The digestion mixture was now poured into twice its volume of 95% ethyl alcohol, filtered, and the nucleosides isolated from the filtrate. 

As previously mentioned, Levene was able to isolate the pyrimidine nucleotides of desoxyribosenucleic acid by chemical hydrolysis but, owing to their instability, the purine nucleotides were destroyed. 

Since partial hydrolysis of desoxyribosenucleic acid gives rise to four nucleotides, and complete hydrolysis gives the four nitrogenous bases in equimolecular proportions, the fundamental molecule of the acid may be regarded as a tetranucleotide. 

According to Miescher, the acid is tetrabasic. However, Levene and Simms found that desoxyribosenucleic acid has one secondary and four primary phosphoric dissociations, a conclusion since confirmed by Bredereck. Levene proposed a formula of type VII for desoxyribosenucleic acid however, since the acid gives rise to two diphospho-desoxyribosylpyrimidines on hydrolysis, he was able to extend that formula by showing alternating purine and pyrimidine residues as follows. 

Signer, et have studied the viscosity and double refraction of flow of one of the more highly polymerized specimens of desoxyribosenucleic acid, and conclude that the molecular weight lies between 5 times... 

A desoxyribonucleo-depolymerase is present in ox pancreas and calf thymus, and in extracts of the germs of Lima bean, sunflower, maize, wheat, and pumpkin. It is not the same as the crystalline ribonucleo-depolymerase, which is devoid of action on desoxyribosenucleic acid. Action of this depolymerase on desoxyribosenucleic acid causes an increase of acidity and conductivity titration of the extra acidity liberated indicates that the final product is a pentabasic tetranucleotide. Greenstein and Jenrette found that the depolymerase also destroys the structural or anomalous viscosity. 

Tetranucleotide Unit of Desoxyribosenucleic Acid (CnHtiO NuP4)... 

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