Determination of the site of synthesis of some Euglena cytoplasmic and chloroplast ribosomal proteins.

Ribosomal protein synthesis during chloroplast development in Euglena gracilis has been studied by using inhibitors specific for either chloroplast or cytoplasmic protein syntheses. Fifty proteins of cytoplasmic and 39 of chloroplast ribosomes have been examined. Synthesis of all cytoplasmic ribosomal proteins is strongly inhibited by cycloheximide. Lincomycin (LIN) seems to have no effect on the synthesis of these proteins. In contrast, formation of 12 chloroplast ribosomal proteins is inhibited by cycloheximide (CHI), that of 9 by lincomycin, and that of 6 by both of these antibiotics; the technique used in this study did not permit definite determination of the sites of synthesis of the remaining proteins.