Chromatography nucleoside pyrophosphates

The isolation of an individual glycosyl ester of a nucleoside pyrophosphate is a rather difficult task. Ion-exchange column-chromatography and preparative, paper-chromatography have been the main methods used for solving problems in separation. 

Preparative, paper-chromatography is frequently used for further fractionation of the resulting mixtures. The high lability of glycosyl esters of nucleoside pyrophosphates seriously limits the choice of solvent systems. Systems used most commonly are neutral or slighdy acidic mixtures of ethanol with ammonium acetate,24,25 or weakly acidic solvents based on 2-methylpropionic acid.26 A solvent system containing morpholinium borate has also been found extremely useful.27... 

Escherichia coli B was incubated with 2,6-diaminopurine (XXIV), and 6-amino-2-(methylamino)-9-(5-0-phospho-D-ribosyl)purine (XXV) was isolated from the acid-soluble extract of the cells. 5-Nucleotidase liberated a nucleoside containing D-ribose. Hydrolysis of the nucleoside (or nucleotide) with N hydrochloric acid liberated 6-amino-2-(methylamino)purine, which was identified by paper chromatography and by its ultraviolet absorption spectrum. The chromatographic and ion-exchange behavior of the extract also suggested the presence of either a pyrophosphate or a triphosphate of the 6-amino-2-methylamino-(D-ribosyl)purine. In a similar manner, 2,6-diamino-9-(5-0-phospho-D-ribosyl)purine (XXVI) was isolated and identified, together with its possible pyrophosphate or triphosphate. 2,6-... 

General. Pyridine is distilled from p-toluenesulfonyl chloride and then from calcium hydride and stored over potassium hydroxide. N,N-Di-methylformamide is distilled from calcium hydride and stored over molecular sieves. Dioxane is distilled from phosphorus pentoxide. Tri-n-butylamine, triethylamine, diphenyl phosphorochloridate, and o- and p-fluorobenzoyl chlorides are distilled before use. Tri-n-butylammonium pyrophosphate is prepared at room temperature according to the method of Moffatt and Khorana and stored at 5°. Paper chromatography is carried out by the descending technique on Whatman No. 1 paper in (A) isobutyric acid-1 M NH4OH (60 40) and (B) 1-propanol-water (7 3). Electrophoresis is carried out on Whatman No. 1 paper at pH 3.5 in 0.035 M citric acid-0.0148 M sodium citrate (1 1). Evaporations are carried out under reduced pressure at bath temperatures below 30°. Phosphate analyses of nucleoside triphosphates are performed by the method of Lowry and Lopez after treatment of approximately 1 / mole of these compounds for 60 min at 22° in 1 ml of Tris chloride at pH 10.4 containing 0.02 mg of alkaline phosphatase of calf intestinal mucosa (type VII, Sigma Chemical Co.). 

Caton-Williams et al7 reported a one-pot synthesis of nucleoside 5 -(a-P-thio) triphosphates (89) and phosphorothioate nucleic acids without protecting any nucleoside functionalities. The chemistry of this faeile synthesis involves the treatment of unprotected nucleosides with a mild phosphitylating reagent (salicyl phosphorochloridite and pyrophosphate) followed by sulfurization and hydrolysis to afford the corresponding analogues. These compounds can be easily purified by ion-exchange chromatography. 

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