[Inhibition by antibiotics of the incorporation of labelled amino acids into the nuclear matrix proteins of the Zajdela hepatoma].

The incorporation of radioactivity into nuclear matrix proteins during incubation of Zajdela hepatoma cells with labelled amino acids was strongly inhibited by chloramphenicol and cycloheximide and slightly inhibited by actinomycin D and mitomycin C. The antibiotics studied inhibited the incorporation of the radioactive label preferentially into proteins with Mr 150 000-220 000, approximately 55 000 and less than 26 000. During incubation of ascites tumour cells with antibiotics, predominantly with chloramphenicol, a decrease in the content of some protein components was observed as well. As in the low molecular weight protein fraction, the intense inhibition of the radioactive label and a decrease of its content was observed, a conclusion is drawn that this protein fraction is characterized by a high turnover rate.