ADSORPTION CHROMATOGRAPHY OF NUCLEOSIDES BY THE RESINS CONTAINING NUCLEIC-ACID BASES

Polystyrene (PS) cross-linked with DVB was chloromethylated and reacted with nucleic acid bases such as adenine (Ade), thymine (Thy), guanine (Gua), and cytosine (Cyt) to give resins containing nucleic acid bases (Ade-PS, Thy-PS, Gua-PS, and Cyt-PS). Each resin was packed in a column, and an aqueous solution of nucleosides was fed to the column. In the case of Ade-PS and Thy-PS, uridine (U) and adenosine (A) were preferentially adsorbed compared to cytisine (C) and guanosine (G), respectively. In the case of Gua-PS and Cyt-PS, unexpectedly, C and G were preferred, respectively. When organic solvents were added in the nucleoside solution, C and G were preferred in the case of Gua-PS and Cyt-PS, and in the case of Ade-PS and Cyt-PS, ratios of the degree of absorption (C/U and AVG) increased. The most effective solvent to prevent the hydrophobic bond between the resin matrix and nucleosides was acetonitrile, and the second was tetrahydrofuran. Ade-PS and Thy-PS were contacted with a mixed aqueous solution U and C or A and G, and the selectivity coefficient (ae or as) was comparable to the value of U/C or A/G. The resins were contacted with a solution of single nucleoside, and the rate and amount of adsorption at equilibrium were measured to find that the rate determing step was the diffusion in resin particles and that chemical adsorption was caused principally by the formation of complementary base pairs (A-T or A-U and GC).