An Influence of 2,6-Diaminopurine upon the Content of Kappa in Paramecium aurelia, Variety 4.

Abstract
The content of effective kappa in Paramecium aurelia killers is markedly reduced by their exposure to 2,6-diaminopurine. This purine uniquely exhibits this capacity among the many purines and pyrimidines tested. The effect is blocked by the simultaneous presence of adenine, adenosine, or adenylic acid.