Of guanylic acid

The phosphodiester bonds of xanthylic acid in deaminated RNA were scarcely split by RNase U2 (30). The susceptibility of purine nucleotide residues to RNase U2 decreases in the order of A>G>I X, indicating that the phosphodiester bonds of adenylic acid and inosinic acid without a keto group at the position of purine base are more sensitive to RNase U2 than those of guanylic acid and xanthylic acid. The resistance of TNP-RNA to RNase U2 may be also attributed to the steric hindrance by a larger substituent at 2-amino groups of guanylyl residues, as with RNase T, (SO). 

Xanthylic and Guanylic Acids. On deamination with nitrous acid, guanylic acid is readily transformed - to xanthylic acid. Consequently, determination of the structure of the latter will serve to show that of guanylic acid also. 

Ribavirin [4.15) is of special interest because of its broad spectrum of attack. It is active against both DNA and RNA viruses. Also known as tribavirin and Virazole , this substance is l-)8-D-ribofuranosyl-l,2,4-triazole-3-carboxamide. In vivo, it is changed to the 5 -monophosphate which inhibits inosinate dehydrogenase, and hence prevents the formation of guanylic acid on which synthesis of both DNA and RNA depend. It is being used clinically for the treatment of viral pneumonia and measles although the results are not quite clear-cut (Smith and Kirkpatrick, 1980). 

H. Hayashi and F. Egami Fractionation and properties of guanylic acid... 

This compound has been isolated after subjecting yeast ribonucleic acid to brief acid hydrolysis. When it is treated with alkali there is cleavage at (1), with the formation and subsequent hydrolysis of a cyclic anhydride of guanylic acid. The final products are guanosine-2 -phosphate, guanosine-3 -phosphate, and cytidine-3 -phosphate. The last two would be split by 3-nucleotidase from barley. 

Qua/nylic Add Solution. Dissolve 0.5 g. of guanylic acid in water to make 100 mb Store in a refrigerator. 

The enzyme catalyzing the amidation of the nicotinic acid- DPN to the active coenzyme has been detignated DPN synthetase q. (3c)]. The mechanism of the reaction is timilar to that involved in the formation of guanylic acid 13S, 1S4) as well as a-N-formylglycinamide in which the glutamine nitrogen is transferred to the acid yielding the amide 133). At present, there is no explanation of the reason for the ATP requirement in the reaction. 

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