Adenylic acid, deamination hydrolysis

The isomerism existing between the pairs of nucleotides was attributed to the different locations of the phosphoryl residues in the carbohydrate part of the parent nucleoside,49 63 since, for instance, the isomeric adenylic acids are both hydrolyzed by acids to adenine, and by alkalis or kidney phosphatase to adenosine. Neither is identical with adenosine 5-phosphate since they are not deaminated by adenylic-acid deaminase,68 60 and are both more labile to acids than is muscle adenylic acid. An alternative explanation of the isomerism was put forward by Doherty.61 He was able, by a process of transglycosidation, to convert adenylic acids a" and 6 to benzyl D-riboside phosphates which were then hydrogenated to optically inactive ribitol phosphates. He concluded from this that both isomers are 3-phosphates and that the isomerism is due to different configurations at the anomeric position. This evidence is, however, open to the same criticism detailed above in connection with the work of Levene and coworkers. Further work has amply justified the original conclusion regarding the nature of the isomerism, since it has been found that, in all four cases, a and 6 isomers give rise to the same nucleoside on enzymic hydrolysis.62 62 63 It was therefore evident that the isomeric nucleotides are 2- and 3-phosphates, since they are demonstrably different from the known 5-phosphates. The decision as to which of the pair is the 2- and which the 3-phosphate proved to be a difficult one. The problem is complicated by the fact that the a and b" nucleotides are readily interconvertible.64,64... 

Inosinic and Adenylic Adds, Similarly, Levene and Harris found that the adenylic acid from ribosenucleic acid can be deaminated to an inosinic acid which undergoes hydrolysis at its own pH to give hypo-xanthine and 3-phosphoribose. On the other hand, Thannhauser had shown that ammoniacal hydrolysis of the adenylic acid gives adenosine and phosphoric acid. 

Oxidation of (8) yielded a ribonic acid phosphate (9), whose properties differed from those of the ribonic acid 5-phosphate obtained by similar hydrolysis and oxidation of inosine 5 -phosphate. Moreover, reduction of (8) allegedly gave a ribitol phosphate (10) which was optically inactive. From these studies, it followed that the phosphoric moiety in (10) is esterified by the 3-hydroxyl group of the ribitol moiety. Similarly, a yeast adenylic acid, obtained from an alkaline hydrolysate of yeast ribonucleic acid, was deaminated to an inosinic acid that was different... 

Japan, pat. 732C86) (to Ajinomoto), C.A. 51, 3870b (1957). Structure Levene, Bess, op. ctt.. pp 187-192 Bredereck, Ber. 66, 198 (1933) Levene, Tipson, J. Biol. Chem. Ill, 3t3 (1935). Also prepd from muscle by enzymatic deamination of muscle adenylic acid Ostem, Biochem. Z. 254, 63 (1932) by hydrolysis of inosine triphosphate Kleinzeller, Biochem. J. 36, 729 (1942). Studies on the enzymatic synthesis Greenberg, J. Biol. Chem. 198, 611 (1951) Korn et al, ibid 217, 875 (1955). Microbial fermentation method using mutant strains of Micrococcus glutamicus Kinoshita el al. U.S. pat. 3,232,844 (1966 to Kyowa). 

There are several pathways available for the degradation of the mononucleotides. For example, adenosine 5 -phosphatc (AMP) is either deaminated hydrolytically to inosinic acid (IMP) by 6 -adenylic acid deaminase (217, iS7) or split directly to the corresponding nucleoside, adenosine, by 5 -nucleotidase 238). The nucleoside inosine resulted from either the hydrolysis of inosinic acid by 5 -nucleotidase or by the action of adenosine deaminase on adenosine 238, 239). The above pathways, as well as other likely conversions of purine compounds to hypoxanthine and xanthine 2JiO) are shown in Fig. 13. Finally, the enzyme xanthine oxidase acted on both the free bases, hypoxanthine and xanthine, to produce uric acid which was the final product of purine metabolism in some animals. 

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