title: Importance of the osmolarity of the incubation medium on amino acid incorporation into protein by isolated rat liver mitochondria.
abstract: 1. Incorporation of [(14)C]leucine into protein by isolated rat liver mitochondria was examined by using incubation media similar to those used by Sandell, Löw & Decken (1967) (medium A) and Roodyn, Reis & Work (1961) (medium B). The incorporation process was found to be almost completely inhibited in medium A. 2. By decreasing the amount of sucrose and omitting tris-hydrochloric acid from medium A, incorporation proceeded at a rate higher than that found in medium B. It was found that the inhibitory action of medium A was due to its high osmolarity. 3. Oxidative phosphorylation and RNA synthesis by the isolated mitochondria proceeded at the same rate in media essentially the same as media A and B. 4. There was a partial inhibitory action of medium A on leucine uptake by the mitochondria and also on the formation of leucyl-transfer-RNA. The major block of inhibition by the hyperosmolarity of medium A seemed to be located at a later step of protein synthesis involving mitochondrial ribosomes. 5. Protein synthesis by Escherichia coli B was only slightly inhibited, if at all, in hyperosmotic media in which protein synthesis by isolated mitochondria was completely stopped.
mesh_terms: D000818:Animals; D002247:Carbon Isotopes; D003470:Culture Media; D004926:Escherichia coli / Q000378:metabolism; D006851:Hydrochloric Acid; D066298:In Vitro Techniques; D008930:Mitochondria, Liver / Q000378:metabolism*; D009994:Osmolar Concentration; D009995:Osmosis; D010085:Oxidative Phosphorylation; D014176:Protein Biosynthesis; D012313:RNA / Q000096:biosynthesis; D012343:RNA, Transfer / Q000096:biosynthesis; D051381:Rats; D013395:Sucrose
chemical_list: D002247:Carbon Isotopes; D003470:Culture Media; D013395:Sucrose; D012313:RNA; D012343:RNA, Transfer; D006851:Hydrochloric Acid