title: The isolation of carcinogen-binding protein from livers of rats given 4-dimethylaminoazobenzene.
abstract: 1. Three azo-dye-binding proteins were identified in the soluble cell supernatant fraction from livers of rats that had received 4-dimethylaminoazobenzene by intraperitoneal injection. 2. One is basic and was highly purified. It has an isoelectric point of pH8.4 in barbital-sodium chloride buffer, I0.1, an S(20,w) value of 3.5s and a molecular weight determined by Sephadex chromatography of 45000. 3. It does not have N-terminal amino acids with free alpha-amino groups. 4. Digestion with Pronase gives rise to a single azo-dye-bound peptide, which on hydrolysis is shown to contain glycine, alanine, serine, threonine, glutamic acid and aspartic acid. The amino acid that binds the azo-dye was not identified. 5. On starch-gel electrophoresis the basic protein separates into a double band, indicating microheterogeneity. 6. The other two proteins were partially purified and occur in a fraction together. They have isoelectric points near neutrality and a molecular weight as determined by Sephadex chromatography of 13800. 7. The absorption spectra in formic acid of both the basic and the low-molecular-weight proteins are similar. The azonium ion has an absorption maximum at 518mmu and another adsorbed chromogen is present with an absorption maximum at 395mmu.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001322:Autoanalysis; D002845:Chromatography; D002850:Chromatography, Gel; D004586:Electrophoresis; D005779:Immunodiffusion; D007274:Injections, Intraperitoneal; D008099:Liver / Q000378:metabolism*; D008297:Male; D010455:Peptides / Q000032:analysis; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D013053:Spectrophotometry; D014461:Ultracentrifugation; D004124:p-Dimethylaminoazobenzene / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D010455:Peptides; D011506:Proteins; D004124:p-Dimethylaminoazobenzene