Oligo-uridylic acids

A column (250 x 4.6 mm) packed with a reversed-phase C 18 support, coated with trioctylmethyl ammoniumchloride, separated oligo-uridylic acids and discriminated between (Up)89 and (Up)q0, (Fig. 23)83). In such high a region of molar mass, the separation of components differing in only one monomeric unit is remarkable in polymer chromatography in general. 

Imidazolides of adenylic acid (ImpA) or uridylic acid (ImpU) are polycondensed to oligonucleotides by means of Zn2+ ions. 1673 The resulting phosphordiester bond was found to be of the 2, 5 type. In the reaction of nucleoside 5 -phosphoric acid methyl ester with ImpA in the presence of MgC, 2, 5 -dinucleotides are formed six to nine times more frequently than the corresponding 3, 5 compounds. 63 Polycondensations of ImpA in aqueous solution in the presence of various divalent metal ions lead to short oligo-adenylic acids (pA) (n = 1—5) mainly with 2, 5 -intemucleotide linkages. With Pb2+, for example, the total yield of oligomers was as high as 57%. 1683 1693... 

For uridylic acid dinucleotides (UpU) and short chain polynucleotides (oligo U), a marked protective effect against e aq attack is observed. The reactivity per nucleotide has been measured as a function of pH for UpU and for an oligo U molecule which contains about 20 nucleotides. The results are compared with those for uracil in Figure 5. In the absence... 

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