Macromonocyclic Polyamines as Biological Polyanion Complexons. 2. Ion-Pair Association with Phosphate and Nucleotides

Article abstract of DOI:10.1021/ja00375a042

The interaction of 15- to 18-membered macromonocyclic tetra-, penta-, and hexaamines with biologically important polyanions, such as phosphate, AMP, ADP, and ATP, in neutral pH solutions has been studied using polarographic methods and 1H NMR shift measurements.The results established 1:1 ion pairings between the polycationic forms of the macrocycles and the polyanionic forms of the phosphates.The inorganic phosphate anion is bound to the macrocycles as strongly as the previously studied polycarboxylate anions.The greater stability constants β_L for the 1:1 nucleotide complexes imply the presence of other binding sites, such as adenine moieties, in the nucleotide molecules.These β_L values are greater than those reported for the nucleotide complexes of physiological linear polyamines (e.g., spermidine and spermine) or of divalent metal cations (e.g., Mg(2+)).The macrocyclic polyamines, moreover, interact with Mg(2+)- and Ca(2+)-nucleotide complexes to yield the ternary complexes.Significant biological implications are discussed.