The effect of 4-dimethylamino-3'-methylazobenzene on 14-C-labelled amino acid incorporation by rat-liver polysome preparations.
1. The incorporation of (14)C-labelled amino acids into polysomal protein was studied in a system consisting of polysomes and pH5 enzyme obtained 4 and 40hr. after a single intraperitoneal injection of 4-dimethylamino-3'-methylazobenzene. Labelling of the polysome fraction of preparations of both the 4hr.-treated and 40hr.-treated rats was considerably higher than in the normal control. 2. In further experiments on protein synthesis by polysomes from azo-dye-treated rats, the effect of replacing pH5 enzyme with cell sap was studied. Incorporation of (14)C-labelled amino acids into polysomal protein was similar to that of the control. 3. Aggregate size of polysomes obtained from rats injected previously with 4-dimethylamino-3'-methylazobenzene was studied by sucrose-gradient centrifugation. Polysomes prepared at 4hr. after azo-dye administration contained a considerable amount of large aggregates (approx. 700s), whereas at 40hr. after administration of the azo-dye the amount of large aggregates was less than in the control. 4. Determination of the ultraviolet spectra of polysome preparations from both normal and azo-dye-treated rats revealed no difference between the preparations. On the other hand, the ultraviolet spectra of cell-sap fractions from the different preparations showed that there is a definite shift in the absorption maximum from 272mmu (normal) to 267mmu, 40hr. after treatment, with an intermediate value of 270mmu for the preparation from 4hr.-treated rats. The absorption minimum changes from 250mmu (normal) to 245mmu for the preparation from 40hr.-treated rats.
D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001391:Azo Compounds / Q000494:pharmacology*; D002273:Carcinogens / Q000494:pharmacology*; D002498:Centrifugation; D066298:In Vitro Techniques; D008099:Liver / Q000166:cytology; D014176:Protein Biosynthesis; D051381:Rats; D012270:Ribosomes / Q000378:metabolism*; D013057:Spectrum Analysis; D014466:Ultraviolet Rays
D000596:Amino Acids; D001391:Azo Compounds; D002273:Carcinogens