Muscle protein biosynthesis in the tumour-bearing rat.  A defect in a post-initiation stage of translation.
1. The decreased ability of polysomes isolated from the gastrocnemius of rats bearing the Walker 256 carcinoma to incorporate L-[14C]leucine into protein persisted in the presence of 5-10-5 M aurin tricarboxylic acid and 1-10-2 M NaF. 2. Poly(U)-directed phenylalanine incorporation by such polysome preparations was less than that of similar preparations from normal rats. 3. The ability of gastrocnemius polysomes from tumour-bearing rats to react with puromycin was markedly decreased. Cycloheximide inhibited peptidyl puromycin formation by polysome preparations from both normal and tumour-bearing rats. 4. The ability of recombined 60 S and 40 S subunits prepared from polysomes of tumour-bearing rats to carry out poly(U)-directed polyphenylalanine synthesis was much reduced when assayed over a wide range of magnesium concentrations. Cross-over experiments with subunits from normal and tumour-bearing animals suggested that this was due to a defect in the smaller ribosomal subunit.
D000818:Animals; D002279:Carcinoma 256, Walker / Q000378:metabolism*; D003509:Cyclohexanecarboxylic Acids / Q000494:pharmacology; D009124:Muscle Proteins / Q000096:biosynthesis*; D009132:Muscles / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000096:biosynthesis*; D010649:Phenylalanine / Q000378:metabolism; D011132:Polyribosomes / Q000378:metabolism; D014176:Protein Biosynthesis / Q000187:drug effects; D051381:Rats; D012270:Ribosomes / Q000187:drug effects / Q000378:metabolism
D003509:Cyclohexanecarboxylic Acids; D009124:Muscle Proteins; D009363:Neoplasm Proteins; D010649:Phenylalanine