title: Purification and photoaffinity labelling of a rat cytosolic binding protein specific for 3-methylcholanthrene.
abstract: Rat hepatic cytosolic proteins which sediment at 4-5 S on sucrose gradients exhibit high-affinity saturable binding for the carcinogen 3-methylcholanthrene. A rat liver protein of Stokes' radius 3 nm, Mr by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of 39,000 and with specific 3-methylcholanthrene-binding activity sedimenting at 4.5 S, has been purified 315-fold to apparent homogeneity by using affinity chromatography on a column of 1-hydroxy-3-methylcholanthrene coupled to epoxy-activated Sepharose 6B, in conjunction with two gel-filtration steps. The protein purified by this technique was shown to be associated with the observed specific 3-methylcholanthrene-binding activity by photoaffinity labelling with 1-oxo-3-methylcholanthrene.
mesh_terms: D000345:Affinity Labels; D000818:Animals; D002352:Carrier Proteins / Q000302:isolation & purification*; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D003600:Cytosol / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D008099:Liver / Q000032:analysis; D008748:Methylcholanthrene / Q000031:analogs & derivatives / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: C027326:3-methylcholanthrene-binding protein, rat; D000345:Affinity Labels; D002352:Carrier Proteins; C052727:3-methylcholanthrene-1-one; D008748:Methylcholanthrene