A spectrophotometric resin competition procedure to determine dissociation constants for metal ion-nucleotide complexes.

The resin competition method for determining the dissociation constants of metal ion-nucleotide complexes was modified to take into account the fact that some metal nucleotide complexes are anionic and thus, like the free nucleotide, will bind to the resin. A simple, rapid spectrophotometric titration procedure is given for the determination of both the metal ion-nucleotide complex dissociation constant and the ratio of the affinities of the nucleotide and its complex for the resin.