[Polyelectrolyte invariance of the acid-base equilibrium in native DNA with varying GC-pair levels].

The influence of the ionic strength of solution on the protonation of the Micrococcus lysodeicticus DNA molecule was studied by means of circular dichroism, spectrophotometric and potentiometric titration in a wide range of the supporting electrolyte concentration ([NaCl] = 0.5-0.005 M).