THERMODYNAMIC ANALYSIS OF THE INTERACTION OF ETHIDIUM-BROMIDE WITH DEOXYTETRARIBONUCLEOSIDE TRIPHOSPHATE 5'-D(APGPCPT) AS INDICATED BY (1)NMR DATA

The temperature dependences of the chemical shifts of nonexchangeable protons of ethidium bromide in a mixture of deoxytetraribonucleoside t riphosphate 5'-d(ApGpCpT) in aqueous solution were studied using an im pulse NMR spectrometer (500 MHz). The methods of calculating the therm odynamic parameters of complex formation were used, which make it poss ible to differentiate the contribution of each of the reactions leadin g to the formation of dye-tetranucleotide complexes 1:1, 2:1 and 1:2 u nder conditions of a complex equilibrium in solution. The values of Gi bb's free energy, enthalpy and entropy for these reactions were estima ted.