Studies on the Stabilities of 5′-Ribonucleotides (III) Analytical Applications of the Dephosphorylation of 5′-Ribonucleotides with Thorium Ion Part 1. A Simple Preparation of Ribonucleosides

• Published in: Food Hygiene and Safety Science (Shokuhin Eiseigaku Zasshi) Vol. 16; no. 3; pp. 153 - 159_1
• Main Authors: KUSUI, Sadao, MURAKOSHI, Akira, MORITA, Taisuke, MORI, Hideyuki
• Format: Journal Article
• Language: English
• Published: Japanese Society for Food Hygiene and Safety 05-06-1975
• ISSN: 0015-6426; 1882-1006
• DOI: 10.3358/shokueishi.16.153

A simple preparation of ribonucleoside (I) from 5′-ribonucleotide (II) was investigated by taking advantage of the dephosphorylation of II with thorium ion (Th (IV)). The decomposition of II to I with Th (IV) was remarkably influenced by a kind of buffer solutions employed. The decomposition was greatly accelerated in acetate (pH 3 and 4), Tris-hydrochloric acid (pH 7), and ammonium (pH 9-12) buffers, but completely inhibited in citrate (pH 4), phosphate (pH 7), and carbonate (pH 11) buffers. An increased reaction temperature in the range of 25 to 100°C tested was advantageous for the production of I from II. The production of I apparently attained equilibrium when Th (IV) was used 4 times the molar quantity of II in acidic media, and 6-8 times that of II in neutral and alkaline media. From the results described above, the most suitable conditions for the decomposition of II to I have been established. For the preparation of a purine I, the corresponding II is treated in ammonium buffer (pH 10) with Th (IV) at 8 times the molar quantity of II at 100°C for 2 hours. For that of a pyrimidine I, the corresponding II is decomposed in acetate buffer (pH 3) with Th (IV) at 4 times the molar quantity of II at 100°C for an hour. All the reaction mixtures treated under the conditions described above were found to be utilized as standards of I, which are examined in the thin-layer chromatography of II described in “The Japanese Standards of Food Additives 3rd Ed”. It has been suggested that I obtained from II can be simply isolated by suitable separation procedures.