| Abstract: | Thermal denaturation was studied for a wide range of magnesium ions concentrations and salt concentration 0.15 M NaCl. It was shown that thermal stability of DNA increases at low Mg/2P ratios and decreases at high concentrations of magnesium ions. Up to Mg/2P = 10 DNA denaturation is an equilibrium process. With an increase in magnesium ions concentrations the enthalpy of DNA denaturation reaches the maximum at Mg/2P = 10 (50 kJ/mole base pairs). DNA aggregation and appearance of a new heat absorption peak is observed in the high temperature region at Mg/2P = 10. At this region of magnesium ions concentrations DNA denaturation process is non-equilibrium. |
