Interaction of 8-hydroxyquinoline Sulfate with Components of Tuberculin Purified Protein Derivative Solutions III: Binding of 8-Hydroxyquinoline by Tuberculin Purified Protein Derivative

Abstract

The interaction between the preservative 8-hydroxyquinoline sulfate and macromolecules present in tuberculin purified protein derivative solutions such as tuberculoprotein, nucleic acid, and polysaccharide was studied. In buffered solution (pH 7.38), 8-hydroxyquinoline sulfate is dissociated to 8-hydroxyquinoline and sulfuric acid, and it is the base 8-hydroxyquinoline that forms a reversible association with these macromolecules. The degree of binding of 8-hydroxyquinoline to tuberculoprotein, nucleic acid, and polysaccharide was shown to be a function of the concentration of these macromolecules. In commercial solutions of tuberculin purified protein derivative, the low concentrations of purified protein derivative used have little effect on the concentration of 8-hydroxyquinoline sulfate. Thus, for all practical purposes the antimicrobial activity of 8-hydroxyquinoline sulfate was not affected.