On the nature of the pneumococcal activator substance.

Abstract

The pneumococcal activator substance appears to be a protein or protein-containing macromolecule. The substance cannot be detected in nontransformable cells and the biological activity shows species specificity. A method for the preparation of high specific-activity activator is described, Dextran gel chromatography and sucrose density gradient centrifugation of the activator suggest a molecular weight in the neighborhood of 10,000. The activator seems to react with some pneumococcal surface structure; as a result of this, the cells acquire the capacity for binding of DNA molecules. Inhibition of protein and/or RNA synthesis during treatment of the bacteria with activator blocks the establishment of competent state.