[Effect of adenosine protonation on its interaction with polyuridylic acid]

The effect of adenosine protonation on complex formation between poly(U) and adenosine has been studied by UV spectroscopy, titration and equilibrium dialysis techniques. A method has been developed to estimate the "misincorporation" of ionized monomer molecules into a polynucleotide--monomer complex. The method is based on combining the titration and binding data. Using this method it is shown that protonated adenosine interacts to some extent with poly(U) in the course of A.2 poly(U) dissociation at acidic pH. Qualitative differences between the effects of ionization of the polymer and monomer components on polynucleotide--monomer interaction are discussed.