Partial purification of a binding protein for polychlorinated biphenyls from rat lung cytosol: physicochemical and immunochemical characterization.
A binding protein for certain methyl sulfone metabolites of polychlorinated biphenyls (PCB) was partially purified from lung cytosol of untreated female rats. The protein has an Mr of 13,000 and a pI of 5.3 in the absence of reducing agents. In the presence of dithioerythreitol or beta-mercaptoethanol, the protein is split into subunits with a more basic pI. The 13-kDa protein was electroeluted from SDS-polyacrylamide gels, and an antiserum against the protein was raised in rabbit. The immunoglobulin fraction was shown to contain monospecific antibodies against the 13-kDa protein as determined by Western immunoblots. The antibodies retained partially purified binding protein labeled with radioactive ligand when subjected to protein A-Sepharose chromatography and caused a shift in the elution of the labeled protein from Sephadex G-75 and a shift in its sedimentation behavior on sucrose gradients. Due to striking similarities in physicochemical characteristics of the 13-kDa protein and a protein purified from rabbit lung and uterus, uteroglobin, the anti 13-kDa protein antibodies were tested for cross-reactivity. As judged by Western immunoblots, the anti 13-kDa protein antibodies did not cross-react with uteroglobin and the two proteins, although similar, do not seem to be identical. The 13-kDa protein is proposed to be responsible for the accumulation of certain methylsulfonyl-PCBs in lung tissue of rats. Monospecific antibodies against the 13-kDa protein should constitute immunochemical probes of great value in attempts to elucidate the physiological role of the protein as well as its possible role in PCB-induced respiratory toxicity.
Lund
J
J
Department of Medical Nutrition, Karolinska Institute, Huddinge University Hospital, Sweden.
Nordlund
L
L
Gustafsson
J A
JA
D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D003600:Cytosol / Q000032:analysis; D005260:Female; D007120:Immunochemistry; D008168:Lung / Q000032:analysis*; D008970:Molecular Weight; D011078:Polychlorinated Biphenyls; D014176:Protein Biosynthesis; D051381:Rats; D011919:Rats, Inbred Strains
D002352:Carrier Proteins; D011078:Polychlorinated Biphenyls