Action of levorin on the incorporation of labelled amino acids into the proteins of Ehrlich ascitic cancer cells

: A polyenic antibiotic levorin had a significant damaging effect on the amino acid transport in the cells of Ehrlich's ascites carcinoma by inhibiting the incorporation and increasing the release of 14C-glycine and 14C-arginine. Inhibiton of incorporation of the radioactive amino acids into protein was observed on both simultaneous addition of the antibiotic and the label into the medium and addition of previously labeled cells into radioinactive medium with the antibiotic. Since in the latter case levorin had probably no effect on the specific radioactivity of the precursor, it was suggested that the decrease in the label incorporation into protein was an evidence of the real antibiotic inhibition of the rate of the synthesis of the polypeptide chain.