Conductimetric study of the binding of Mn2+ to bovine pancreatic deoxyribonuclease.

The binding of Mn2+ on bovine pancreatic deoxyribonuclease has been studied by a conductimetric method. At low ionic strengths, a high-affinity single binding site is demonstrated. The association constant value (K = 1.2 x 10(5) M-1 at pH 8) is high enough to conclude that, in standard experimental conditions for DNA hydrolysis, the reacting species is the DNAase-cation complex. Competitive binding studies in presence of Mg++ and Ca++ show that these cations do not bind on the Mn++ site.