Desoxyribose-l-phosphate

F8. Friedkin, M., Desoxyribose-l-phosphate. II. The isolation of crystalline desoxy-ribose-l-phosphate. J. Biol. Cherti. 184, 449-459 (1950). 

Desoxyribose-l-phosphate has been obtained as the crystalline cyclo-hexylamine salt. It is even more acid-labile than ribose-l-phosphate. Thus, 50% of the phosphorus is released as inorganic phosphate within 10 to 15 minutes upon hydrolysis at pH 4, at 23°C. The equilibrium favors synthesis. It is felt that the same enzyme catalyzes the phosphorolysis of hypoxanthine riboside and hypoxanthine desoxyriboside, because the Michaelis-Menten constants are nearly identical and there is no summation of rates with both substrates present at optimal concentrations. Furthermore, nucleoside phosphorylase purified from horse liver is active with both nucleosides and desoxynucleosides. ... 

The ribose phosphate normally present in cells is jS-D-ribose- 1-phosphate it is very add-labile. Desoxyribose-l-phosphate is even more unstable in add solution at pH 4-0 at room temperature, it is 50% hydrolysed in 15 minutes. It is hydrolysed in the course of estimations of inorganic phosphate and is consequently often measured as such. 

The furanose form of D-ribose is required for the enzymatic phosphorolysis reaction. Pyranose-ribose-l-phosphate will not react with hypoxanthine to liberate inorganic phosphate. On the other hand, desoxyribose nucleosides are quite reactive ... 

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