title: The isolation and characterization of polycyclic hydrocarbon-binding proteins from mouse liver and skin cytosols.
abstract: The major protein to which metabolites of methylcholanthrene are covalently bound has been purified from C3H mouse liver cytosol. Its properties are identical to the mouse skin h-protein, which may be primary arget of carcinogenic hydrocarbon metabolites during transformation to caner. It has a molecular wight of 44,000, consists of 2 subunits o- M.W. 20,000, has an isoelectric point (pI) of 8.05 to 8.6, and a sedimentation coefficient of 3.6 S. These physical properties are rather similar to those of ligandin, a hepatic protein that binds carcinogen metabolites, steroid anionic metabolites, bilirubin, and exogenous organic anions, but not to those of the rat liver azo dye carcinogen binding 'slow h-2-5S' protein. The h-protein and ligandin consistently give different pl values. Two minor basic proteins (molecular weights around 44,000 each), to whcih methylcholanthrene metabolites are convalently bound, have been separated from the h-protein by carboxymethyl-cellulose chromatography. Prelininary results indicate that these 2 minor proteins are related to ligandin. A protein to which methylcholanthrene is noncovalently bound was also identified in the acidic fraction of the mouse liver and skin sytosols and has been partially purified and characterized. It has a molecular weight of 60,000, a pl of 5.0, and a sedimentation coefficient of 4.5S.
mesh_terms: D000818:Animals; D002845:Chromatography; D003600:Cytosol / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D007525:Isoelectric Focusing; D008099:Liver / Q000032:analysis*; D008297:Male; D008748:Methylcholanthrene / Q000378:metabolism*; D051379:Mice; D008809:Mice, Inbred C3H; D008970:Molecular Weight; D011485:Protein Binding; D011506:Proteins / Q000302:isolation & purification*; D012867:Skin / Q000032:analysis*
chemical_list: D011506:Proteins; D008748:Methylcholanthrene