EFFECT OF ANTIBIOTICS AND INHIBITORS ON M PROTEIN SYNTHESIS

Abstract

This work extends the ob-servations of Fox and Krampitz on M-protein synthesis in nongrowing cells of streptococci. A survey of a large number of antibiotics and other potential inhibitors was made. Some substances bring about inhibition of fermentation and inhibit M-protein synthesis because they deprive the cell of the energy needed for this process. A second group of substances inhibit growth at concentrations tenfold or more lower than they inhibit M-protein synthesis. These are the antibiotics which inhibit synthesis of cell wall or other structures in growing cells but do not affect protein synthesis. A third group of substances inhibit growth and M-protein synthesis at the same concentration. These substances probably inhibit growth because they inhibit general protein synthesis and are therefore specific inhibitors of protein synthesis. In this class are chloramphenicol, erythromycin and the tetracyclines. Several other antibiotics of previously unknown mode of action are in this class. A fourth group of substances had no effect on M-protein synthesis. No substances were found which inhibited M-protein synthesis at a lower concentration than that which inhibited growth. M-protein synthesis in nongrowing cells may be a useful model system for obtaining a detailed understanding of protein synthesis.