Effect of sedimentation through sucrose solutions on the protein-synthesizing ability of rat liver microsomes.
1. Centrifugation of the postmitochondrial supernatant of rat liver through 1.0m-sucrose produces particles that have 85-95% less incorporating ability in a cell-free protein-synthesizing system than either ribosomes or microsomes. 2. The incorporation of [(14)C]phenylalanine into protein by particles prepared by sedimentation through 1.0m-sucrose is stimulated about 20-fold by addition of poly U. 3. The content of rapidly labelled RNA of microsomes is decreased during centrifugation through 1.0m-sucrose. 4. It is suggested that degradation of mRNA occurs during the formation of the pellet in the centrifuge tube as a result of a membrane-bound alkaline ribonuclease, after removal of the ribonuclease inhibitor of the soluble fraction.
D000818:Animals; D002247:Carbon Isotopes; D002499:Centrifugation, Density Gradient; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D008862:Microsomes, Liver / Q000032:analysis / Q000201:enzymology / Q000378:metabolism*; D010649:Phenylalanine / Q000378:metabolism; D014176:Protein Biosynthesis; D012313:RNA / Q000032:analysis; D051381:Rats; D012260:Ribonucleases / Q000032:analysis; D012270:Ribosomes / Q000201:enzymology / Q000378:metabolism; D013395:Sucrose
D002247:Carbon Isotopes; D010649:Phenylalanine; D013395:Sucrose; D012313:RNA; D012260:Ribonucleases