Novel prebiotic model systems: interactions of nucleosides and nucleotides with aqueous micellar sodium dodecanoate

The partition coefficients, K-values, of adenosine, guanosine, cytidine, uridine, 5¹-adenylic acid (AMP), 5¹-guanylic acid (GMP), 5¹-cytidylic acid (CMP), and 5¹-uridylic acid (UMP) between water and aqueous sodium dodecanoate has been determined by gel filtration on Sephadex G-25. Below the critical micelle concentration of the surfactant, K-values for all nucleotides and nucleosides are similar. Differential uptake of the four nucleotides and nucleosides is observed, however, by micellar sodium dodecanoate. K-values for adenosine, AMP; guanosine, GMP; cytidine, CMP; and uridine, UMP are 6.16·10³, 9.52·10³; 12.0·10³, 14.6·10³; 19.6·10³, 19.6·10³, 34.2·10³ and 40.3·10³. Similar K-values for corresponding pairs of nucleotides and nucleosides imply that the predominant interaction is between the pyrimidine or purine rings of the substrates and the charged Stern layer of the surfactant. Prebiotic significance of these results is discussed.