Polyamine and magnesium contents and polypeptide synthesis as a function of cell growth

Abstract

The polyamine and ribosome contents during the logarithmic phase of growth were much higher than those in the late logarithmic or stationary phase of growth. On the other hand, the Mg 2+ content did not vary markedly throughout the different growth phases. These data, together with the results of a previous communication (1), suggest that increased polyamines during the logarithmic phase of growth may play significant roles not only in the neutralization of the negative charges of increased ribosomes but also in the increase of the velocity of polypeptide chain elongation by binding to the ribosomes. The polyphenylalanine synthetic activity of ribosomes from the logarithmic phase of growth was higher than that of ribosomes obtained from the stationary phase of growth in the presence of optimal concentrations of spermidine.