The precipitation of polyanions by long-chain aliphatic ammonium salts. 6. The affinity of substituted ammonium cations for the anionic groups of some biological polymers

Abstract

The concentration of sodium chloride needed to dissolve complexes of the polyanions heparin, deoxyribonucleate, hyaluronate, alginate and dextran sulphate with long-chain aliphatic ammonium detergents decreased with increasing degrees of methylation of the cationic nitrogen. The concentration of ammonium chloride and its methyl derivatives needed to dissolve the cetylpyridinium complexes with the same polyanions increased with increasing degrees of methylation of the cationic nitrogen. Guanidinium chloride and ammonium chloride were comparable except that the deoxyribonucleate complex dissolved in a more dilute solution of the former. It is assumed that there is competition between the cations of solvent salt and detergent, and the results are discussed on this basis. The relevance of these results to systems in which there is binding to polyanions of substituted ammonium compounds is discussed.