Biopolymers and cell. 1992. 8 (1): 56 - 62

KRUGLOVA E. B.

Spectrophotometry Analysis of Behaviour of DNA Solutions in the Water and at Low Ionic Strengths

Summary

    Studies on temperature changes in vibrational spectra of aqueous solutions of isocytosine (i-Cyt) and its model compounds in the range from 23 °C to 98 °C are aimed at revealing rare tautomeric forms of i-Cyt in solutions and at clearing up physicochemical conditions of their existence. IR-spectra of methanol solutions of the above compounds are obtained. Spectral analysis and comparison between results obtained and literature data allow to conclude that tautomeric equilibrium of i-Cyt is of keto-amine — keto-imine type. The supposition of the energetic advantage of the existence of the tau-tomer with lesser dipole moment due to the lesser polar environment gives and argument for the increase of the rare imine form concentration at the increase of the solution temperature.